Would it be possible for you to copy the contents of the script into a .txt file and post it as an attachment? I am not sure what an edit script is. Does this happen if you use your contacts? How about if you send to a brand new email address that is not in contacts?
In either case run a full virus scan and Download, update and run a full scan with the free version of http://www.malwarebytes.org/lp/lp4/?gclid=CJbZ1KHprrgCFUyi4AodOnwA5g
Scans are best run in safe mode + not connected to the internet ... but be sure the definitions are up to date first.
(Press F8 after power on to get to safe mode)