Which "Adobe" software are you trying to update? Ado0be Shockwave for Director, Adobe Flash or Adobe Reader?

If it's the Adobe "Shockwave Flash" plugin then see the article, Flash Plugin - Keep it up to date and troubleshoot problems.

If you still have problems updating your Flash player, try the full, off-line EXE installer for Windows plugin-based browsers, available here:

http://www.adobe.com/products/flashplayer/distribution3.html

After downloading the install_flash_player_18_plugin.exe file your desktop or other easy-to-find location, exit Firefox completely and double-click the file you downloaded.

And for the Adobe Acrobat (PDF) plugin, Adobe is not offering the latest point update in the 11 series for direct download. Instead, go into Adobe Reader (or Adobe Acrobat, if you have that) and use the Help menu to Check for Updates. Then you should be able to get up to 11.0.11.

The plugin checker site still might view that as outdated because Adobe has released a new product named Adobe Reader DC. I don't recommend that for XP users; you'll just have to trust Adobe's updater for Reader XI/Acrobat XI to keep you up-to-date.