NIS 2009 Keeps Deleting File

I just got a new laptop and installed NIS 2009 instantly (plan on upgrading at the end of the month when my subscription runs out and I get paid again). I'm transferring files from the old machine to the new one, and the old one has NIS installed on it, too. There's one file that the new machine keeps deleting, saying it has a trojan. This file doesn't have a trojan; I've used it on several machines, never had an issue with it, and NIS has never before squawked about it. Every time I try and move the file, it gets deleted, both on the new machine and the flash drive being used to transfer it. I have added it to the Scan and Auto Protect exclusion list, tried restoring it from Quarantine, and have it moved right back to Quarantine. What am I missing? Like I said, it's never been an issue on the other machines and it's driving me a bit batty. Thanks for any help you can offer. Sorry if this has been brought up before, but when I searched, the only tip I found was about the exclusion list.