Actually, I'm not interested, though I appreciate the link. There are no viruses written to infect Mac OS X. There are all of about 40 that can infect Mac OS 9.
I run an antivirus program, and I think we all should. However, its more so I don't pass viruses along to my Windows using friends, at at least at this point.
ClamX, a free product, or more properly donationware, has worked well for me.
Anyhow, to the problem at hand. Could you tell me the version of Communicator you are running? It probably won't matter as loing as it is up in the 4.7 range.
You have found your profile folder in the default location, and verified that your mail is there, but NC 4 does not find the profile.
Before doing anything else, make a backup copy of the profile folder, and store it somewhere outside the System Folder.
Next open NC 4's Profile Manager. You will find it in the Netscape Communicator Folder in Applications (Mac OS 9). Create a new profile, with the exact name of the old profile. Hopefully Communicator will find the old profile folder and use it. That would be the easiest fix, if it works.
If that doesn't work, we create a new profile and migrate the data from the old to the new.
One thing that may be instructive would be to open Netscape 7.02's Profile Manager. It can be found in the Netscape Folder, in Applications.
When it opens, does it list the Communicator profile on its list?
UserAgent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X 10.5; en-US; rv:1.9.1b3pre) Gecko/20090223 SeaMonkey/2.0a3