Timber--I can't delete twaintec.dll !!

hello- I'm new to all this. I have that darned offeroptimizer crap on my pc, and am trying to follow timber's plan (post 611527) to fix that situation. I turned off system restore, and ran the regsvr32 c:\windows\twaintec.dll and it said it was sucessful. I did delete one file that was twaintec (configuration settings) but was unable to delete the dll. one! How should I proceed? Do I continue on with the directions, or do I need to get rid of that file first? And if so, HOW? I tried to rename it and delete it, but it didn't work. It always says "access is denied. make sure the disk is not full or write protected and that the file is not currently in use." Please help me? Thank you in advance!!