This error occurs when the path for the output model does not exist. This is an error that happens at the compile stage and will happen if you are compiling straight from WWMT or by compiling manually from the batch file.
Anvil embeds reference to a script in your 3ds Max scripts folder. If that file is missing, there can be an error.
Anvil embeds some scripts for scene startup to protect displacements from being invalidated via improper manipulation. Older versions of Anvil referenced a file that could cause an error if missing.
This error occurs if you are trying to compile an image that has a dimension that isn't a Power of 2.
Bringing life to your scenes
Detailer is a detail sprite primitive plugin with exporters. The tools allow you to either create VBSP files, and will also create geometry that exports into the Source Game Engine with the Wall Worm VMF exporter.