Map Build Errors
If you Rebuild your map or use the [Map Check]? tool, and the engine determines that there is a problem, you may see the errors shown below.
You are encouraged to add any errors that you don't know what they mean; someone will fill in an explanation (probably within a day or two) and it will expand this database. 
Format
The "Rebuild Errors" dialogue is split into 2 columns: one which lists the offending actor (on the left) and one which displays the issue (on the right). Double-clicking on an actor in the left column performs the same function as finding one in the Actor Search window: all viewports will zoom directly to that actor. The 3D viewport will place the camera over the actor, but the 2D viewports will maintain their distance.
Map Check errors are usually not actor-specific, and so only have one column (which reports the error, but not its source).
Note that the error messages listed below consist of the text that appears on the right-hand column of the Rebuild Error Dialogue, or in the Map Check dialogue.
Also note that the letters X and Y are replaced with numbers to identify the actor in the actual error message.
The errors are grouped first by type, second by location, and third alphabetically, ignoring spaces.
Errors
The exact wording of the errors may differ slightly depending on which location it appears (if it can appear in both the Map Check dialogue and the Rebuild Error dialogue).
Botpathing Errors
Map Check and Rebuild Errors
- "Cannot Reach NavigationPoint X from this node!"
- This rare message occurs if a path has been forced between two NavigationPoints but the path is invalid, or occasionally if a pathnode is too far from an objective (like a CTF Flag) and the engine feels that there should be a path connecting the objective to the node. If the problem is the first, simply unforce the path or adjust the location of the nodes. If the problem is the second, just add some pathnodes in between.
- "JumpDest has no forced paths to it"
- You've added a JumpSpot but have not forced any paths to it. You must force a path to it in order for bots to notice it.
- "Ladder Volume is not a ladder volume"
- There is no Ladder actor in the LadderVolume. You probably moved it accidentally, or have deleted the one that spawns there by default.
- "Navigation point embedded in world geometry"
- You've placed a pathnode ouside of subtracted space. Simply delete the node or move it back inside.
- "Navigation point is not on valid base"
- You've placed a navigation point on either a mover or a nonsolid actor. Move it to an appropriate spot on flat, solid space.
- "No forced destination for this jumppad!"
- You've added a UTJumpPad, but have not forced a path from it to a JumpSpot. To get a UTJumpPad to work correctly, this must be done. Remember that the UTJumpPad's Properties>>Navigation Point>>ForcedPath array must contain the actual name of the actor, not the Tag. The name of an object is found under its Properties>>Object>>Name, and will be something like JumpSpot0.
- "No navigation point associated with this mover!"
- If the specified mover is a lift, you have not placed a LiftCenter and/or LiftExit and associated them with the mover. If the specified mover is a door, set its Properties>>AI to bAutoDoor=True or bNoAIRelevance=True. If the mover is neither, then set its Properties>>AI to bNoAIRelevance=True.
- "Pathnode X should be JumpDest for Pathnode Y"
- Pathnode X is at a hard-to-reach location from Pathnode Y's position, and so a jumpspot should be placed there to make bot navigation easier.
Rebuild Errors
- "Navigation point is too close or on too steep a slope"
- You've placed a navigation point too close to a steep slope or too high above the ground. Move it to a flat, solid area, move it closer to the ground, or delete it. Often occurs when pathing is done before terrain is finished, and the terrain is raised above the existing navigation point.
- "No paths from Pathnode X"
- Just what it says: there are no paths to the pathnode specified. To solve this issue, add pathnodes to connect the node in question to the rest of the network. Occurs when paths are forced to a pathnode, or when a pathnode is at the bottom of a steep drop. Often occurs in conjunction with the next error.
- "No paths to Pathnode X"
- Just what it says: there are no paths from the pathnode specified. To solve this issue, add pathnodes to connect the node in question to the rest of the network. Occurs when paths are forced from this pathnode, or when a pathnode is at the top of a steep drop. Often occurs in conjunction with the previous error.
- "Pathnode X is too close to Pathnode Y"
- You may have accidentally duplicated a pathnode; just move one of the offending pathnodes away or delete it. This error always occurs in pairs.
- "May be too close to other navigation points"
- The actor highlighted adds to the bot path network, but is likely colliding with other bot path network actors, like NavigationPoints or Pickups. Delete or move the highlighted actor or ones close to it. Too many NavigationPoint actors too close together will cause AI navigation problems in game.
Map Check Errors
- "Only X Playerstarts in map!"
- Probably occurs if there are less playerstarts in the map than the maximum playercount.
- "Paths need to be rebuilt"
- Exactly what it says: rebuild your botpathing network. This error will be shown if you use the Map Check tool after changing anything in the botpathing network until you rebuild paths.
- "Path to Pathnode X is very long–place a pathnode in between."
- This error even gives you the solution: There are close to 1024 units between Pathnodes X and Y, and it's a little to far for bots to navigate comfortably. Place a pathnode between the two offending nodes to solve this issue. Often occurs in pairs.
- "Playerstart not useable"
- Occurs if a playerstart is either hanging in midair, sitting on a mover or nonsolid brush, or embedded in a solid space. Often coincides with other similar errors. To fix, find the offending playerstart and move it to an appropriate location.
Build Errors
- "Brush X has NULL material references" (Map Check and Rebuild Error)
- You did not apply a texture to a brush. Don't be too alarmed, because it will still have the default engine texture. This is not an issue that must be fixed (but it's probably a good idea). Note that the Map Check error does not specify the brush.
Lighting Errors
- "There are no lights in this map!" (Map Check Error only)
- If you need help to figure this one out, you should probably give up mapping right now.
