When adding a Theme to a View, opening a Project, or turning on a Theme ArcView returns the error;
Stop: Assertion "Number of bits in range" failed at line 351 of file "../base/bitmap.c"
The shapefile is corrupt.
Restore the shapefile with a back up copy. If no backup copy is available you may have luck repairing the shapefile with the Shapechecker utility. Andrews ArcView Page has a utility to do this (see link under Related Information). Click 'How to / Useful' on the left and then ShapeChecker. Follow Andrew's instructions to download and use the utility.
The ShapeChecker Utility is a third party application and is not supported or guaranteed by ESRI. We recommend backing up your files before performing any operation with this utility.
To avoid future file corruption refer to the 'Maximize your system's resources . . .' document under Related Information.