You will need to reinstall/repair "Apple Mobile Device Support" before you can then successfully uninstall it. Here’s what I experimented with and I was successful (I also use Windows XP):
1) Once you are in Add or Remove Programs and have selected "Apple Mobile Device Support", click on "Change" (don't click on Uninstall again since that obviously won't work)
2) In the "Repair or Remove Apple Mobile Device Support" dialog box select "Repair" which will reinstall Apple Mobile Device Support, replacing missing or damaged files
3) After the reinstallation/repair of the Apple Mobile Device Support program is completed, then select Apple Mobile Device Support again in Add or Remove Programs and click on "Remove" this time. This time, Apple Mobile Device should successfully uninstall
4) After you have successfully uninstalled Apple Mobile device support, you can then of course proceed with uninstalling the remaining programs (Bonjour, Apple Application Support) and removal of any files that are still left as directed in the following link: HT1925: Removing and Reinstalling iTunes for Windows XP
5) You can then of course proceed to download and install the newest version of iTunes
I assume you were following the directions or something similar to the above link I put in step 4 of my directions but I provided the link anyway in case you or anyone else may need it for review or reference. Once I was able to uninstall Apple Mobile Device Support, uninstall the remaining programs, remove any leftover files in Program files and empty my trash bin, I was then able to successfully install iTunes 11.1.4.62 and it runs well and syncs fine with my iPod Nano. I hope you have the same success.🙂 Thanks to the helpful user, turingtest2 from London for the above link about how to remove and reinstall iTunes for Windows XP which I am passing on (in case anyone needs to reference it) and his insights into fixing the iTunes 11.1.4 failed install problem. However, I did of course have to figure out the Apple Mobile Device Support failed uninstall problem by myself.
From what I understand, for people who don't have an iPhone (such as myself), the Apple Mobile Device Support program does not even need to be on your computer. However, I leave it there because I'm hesitant to mess around with uninstalling any programs of iTunes that installs as a package for fear that it might mess something up, as Apple's software can be buggy (needless to say).