I know the title's a bit messed up, I cant think of a better way to put it. But anyway, I downloaded an add-on for beemod (tspenAddons_39) and although I now have a lot more styles and items to choose from, but PTI just refuses point blank to compile the maps when I press the "Build and Play puzzle" button, I get the "Build Error, there was an error building the puzzle", no matter what style or items I'm using. Have I screwed something up or is the "update" that was recently released just making everyone's PTI not work? Is there a way I can fix this? The main reason I downloaded the add-ons anyway is because I wanted to try out some those new items and see what they do. Better yet, rather than just telling me that there was an error, why doesn't it just tell me WHAT ACTUALLY WENT WRONG, I might then be able to fix it myself without having to ask for help.

If you open the developer console after the error appears it should print out what the actual error was. You could check there (it's usually me not coppying over a required instance), or open the preview.log in portal 2/sdk_content/maps/styled/.

Ah thanks, that shed a lot of light on the subject, I had a look at what the developer console says, and at the bottom I see this:

could not execute the command:
"c:/program files (x86)/steam/steamapps/common/portal 2/bin/vbsp.exe" -entity_limit 1750 -game "c:/program files (x86)/steam/steamapps/common/portal 2/portal2/" "c:/program files (x86)/steam/steamapps/common/portal 2/sdk_content\maps/preview.vmf"
Windows gave the error message:
"The system cannot find the file specified."

VBSP failed.

Failed to start process ("c:/program files (x86)/steam/steamapps/common/portal 2/bin/vbsp.exe" -entity_limit 1750 -game "c:/program files (x86)/steam/steamapps/common/portal 2/portal2/" "c:/program files (x86)/steam/steamapps/common/portal 2/sdk_content\maps/preview.vmf") with working dir (c:/program files (x86)/steam/steamapps/common/portal 2/bin/)

So it looks as if vbsp has somehow mysteriously vanished, and yes when I looked in the folder where it's supposed to be, it's not in there! At least now I know what the problem is, so that's one thing of my mind, but how do I get it back?

Vertify your game cache, then run the style change.exe in your portal 2 folder. That should fix it up.

I tried verifying my game cache, it did fix the problem with the puzzlemaker, but as soon as I run style-changer it breaks it again.

Try reinstalling the original BEE2, then mine. You might be missing the vbsp_styles.