if the wincache file is corrupt, you don't need to rename the config folder, only delete that file with DW shut down.
as for what causes the cache file to become corrupted, that can be any number of things.
Dreamweaver extensions are javascript based. When you open an extension the first time, the javascript is compiled and saved to the cache file. when you open the server behavior again, it uses the compiled script in the cache file. If it compiles the behavior wrong, the cache file becomes corrupted.
