It is apparently an ad Cookie placed on the machine by doubleclick. Deleting it [should] not be a problem. You didn't mention any specs regarding you system. If you are using a Windows XP operating system go to > Start > All Programs > Accessories > System Tools > Disk Cleanup. Select all options except Off line web pages, Compress old files, and Indexing. click OK > Yes.

If that doesn't work, download and istall MoveOnBoot. Attempt to remove then file using moveonboot.

If that doesn't work, post the problem in the Viruses & security alerts forum

Charlie