OK, sort of reached a situation where I can use my VST plugins. It must have been that the 32-bit plugins were causing Renoise to crash, but I’m not sure…
Questions like these are easier to answer if you provide more detail: Operating system, version of Renoise (and if 32 or 64-bit), maybe some system details (CPU, how much RAM), specific VSTs that are crashing (and if 32 or 64-bit), and your VST folder path.
There was another thread on the forums not too long ago on a similar topic. A few people said they had fewer issues (or none) by using a custom VST path (at least on Windows) that avoided system paths.