Firstly, when installing Mac OS X 10.6 Snow Leopard, make sure that you select "Rosetta". I believe Netscape 7.2 (for Mac OS X) is not in Universal Binary.
Install Netscape 7.2 on your Mac, create a user profile with the same profile name if possible. Quit Netscape 7.2 (not just close the Netscape 7.2 window, but Quit it).
The software should create a profile folder under
[tt]~/Library/Mozilla/Profiles/(Netscape profile name)
Where [tt]~[/tt] denotes your Mac OS X user's folder, i.e. [tt](Macintosh HD) Users/(Mac user name)
/[/tt], and [tt]salted_name[/tt] denotes randomly generated letters.
reference: Netscape 6/7 Profile Location
Next, you should copy (or transfer) files under Netscape's profile folder on PC to respective profile folder (above) on Mac.
Launch Netscape 7.2 (on Mac) and see if it works.
If so, quit Netscape 7.2, and I recommend upgrade to Seamonkey for your web browsing and emailing.
UserAgent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:22.214.171.124) Gecko/20090824 Firefox/3.5.3