Problem with NIS 22.5.x.x on WinXP

Recently reported a problem with NIS 22.5.x but the thread is nowhere to be found (has it been deleted!??).  Anyway, I'll repost...

Have been an NIS user for many years.  Unfortunately after recently (automatically) updated to NIS 22.5.xx from 21.7.xx on WinXP (SP3 Eng, x86, 4GB RAM), found it is crashing the following programs:

1. Adobe Acrobat 8 (v8.3.1 here): Within 10-15 seconds after launching (and without necessary doing anything), up to three error boxes appear:
a. Font Capture/Acrobat.exe error: "The instruction at "0xXXXXXXXX" referenced memory at "0xXXXXXXXX", The memory could not be "read/written". Click on OK to terminate that program (or CANCEL to debug)"  Clicking debug quite the problem but clidking OK results in the following
b. Microsoft C++ Runtime Error (R6025 pure virtual function call).  Clicking OK results in
c. "The instruction at "0xXXXXXXXX" referenced memory at "0xXXXXXXXX", The memory could not be "read/written". Click on OK to terminate that program"

Problem repeats unless the Updater.api plugin from the programs folder is disabled.  Also with the said plugin active, clicking on "Check for update" under Help menu will instantly result in the said error;

2. Firefox (v37.0.2 here): clicking an email link results in the same error message (a) from above (down to the 0xXXXXXXXX values).  Program quits than restarts.  No remedy can be found for this error.

Screen caps are available upon request (can't post them here due to attachments restriction).

Disabling smart firewall and antivirus auto-protect do NOT fix the said errors under XP.

However, under Win7 (SP1 Eng x86) with the same Acrobat 8 installed, error 1 does not occur (ie. no updater plugin conflict), although error 2 has not been tested.

Now I've reverted to NIS21.7.xx via a system rollback (Ghost actually) and the aforementioned errors do NOT occur.  Can someone tell me what's going on here??  Does that mean, NIS 22.x.x is buggy on WinXP?  My subscription with v21.7.xx expires in 6 months and now I don't even know if I should upgrade to a new version, or  just upgrade the subscription itself instead.

Can somebody please help?  And BTW, if for any reason I need to reinstall NIS v21.7.xx again, where should I download the installer files?  And should I run Norton Cleaner Tool beforehand, or simply reinstall v21.7.xx over v22.5.xx??