Really? Every checker shows as virus? Hmmm, that doesn't sound right.
Regardless, if it false positive, that is fine, but if so there should be a scan done and included with the file or the post if they want people to ignore it. Usually false positives only trigger some of the AVs due to the trigger being proprietary, so the AV group that shares the structure will flag it and the other companies wont.
You just use Virus Total, like the great and amazing Frog did here: You must be logged in to see this link.
A fine example is shown here: You must be logged in to see this link. where the first AV company flags and no others do.
So, it is free to scan and easy to do....I think when people don't do it, it makes people wary.