There are an awful lot of patches for Apps. They tend to be, reasonably well, documented at metalink as indeed do errors with them. My experience here, which is very slight indeed, is that the type of error that you may encounter can be greatly affected by your setup as well, i.e is the database RAC or not, do you have shared APPL_TOP, do you have merged APPL_TOP, what modules do and don't you have and so on.