The cause of the problem is Project64 1.5 beta 1, because Project64 1.5 beta 1, including the GFX renderer plugin is based on Project64 1.4 code, and thus includes Jabo's Direct3D 7 GFX 1.4 plugin, but with majorly little bug fixes to allow some more Nintendo 64 games to work, AFAIK, only a fix for majorly little games, and possibly has only a bug fix for Twisted Edge Extreme Snowboarding and it don't have the 64 MB ROM memory error bug fix. Because Project64 1.5 beta 1 is mostly based on Project64 1.4 code, most of the bugs that exist in Project64 1.4 *will* exist in Project64 1.5 beta 1.
You are required to download Project64 1.5 final to fix the 64 MB ROM not enough memory for ROM bug.