Uninstalling spyware programs-unins000.dat does not exist

I'm having a problem with my MSN software, and their techies have recommended that i remove spware programs which are always running. That said, i attempted to remove Spysubtract (that was not always running, but was a superfluous program) and Spyware Blaster, and with each attempt received this message: "unins000.dat does not exist, cannot uninstall."  Dont know what a "dat" file is or what to do next.  I want to retain my Ad-Aware and Spybot and I have disabled SpywareGuard, while the MSN techies are trying to help me.  I understand those are sufficient programs to guard against Spyware, but would like to remove the others, just in case the MSN folks are correct. Any suggestions are welcome. Thank you.