Did you check this document for the known issues:
Troubleshooting: FRM-92090 When Opening any Form (Doc ID 433023.1)
1. The Registry.dat file was modified and now is corrupted
2. This happens when the FORMSxx_MESSAGE_ENCRYPTION is set to true/1.
3. If you issue a ulimit -a at the command prompt you receive the following output:
1. Restore the original Registry.dat file and restart the OC4J / WLS_FORMS.
2. Set the FORMSxx_MESSAGE_ENCRYPTION environment variable to
3. use ulimit -n xxx where xxx is the new number
For example if you have 300 users connecting, set it to a number higher than 300. In our case, we increased it to 128 and were able to connect with 123 users instead of failing with the 61st user.