I have built a custom module for my site that serves as a specialized document manager.  I have set the Default Cache Time to -1, as performance is not a priority for this particular module.  When a user is authenticated, it works fine.  However, postbacks from this module from unauthenticated users are cached (even though I specifically turned caching off) and simply do nothing. I did not have this problem in 4.09.05.  I am having the problem in 5.06.02.  I have searched all the other forum posts, as well as other resources on the internet, and have not been able to find any help with my problem.

Wow, yep, that was it.  I changed the value to -1 and changed the Output Cache Provider setting to "None Specified", and even though the setting keeps changing itself back to "File", the "-1" value stuck and my problem is now fixed.  That was really fast! Thanks a lot!