Sorry to post for a third time, but this is yet again another info.
The download scanner (
http://lxr.mozilla.org/seamonkey/source ... canner.cpp ) uses the IOfficeAntiVirus interface, which is basically the api for ie&office for document scanning.
A simple way to make sure that firefox does not scan your files, is to disable this interface, which is implemented by <insert>.
Of course that will disable globally that interface, so use at your own risk, and only if, like me, you only use your antivirus to manually scan files when you deem necessary.
Here's instructions on how to disable it(use at your own risk, though, it should be safe):
Start regedit:
1-Search for instances of {56FFCC30-D398-11d0-B2AE-00A0C908FA49} (which is the uid for IOfficeAntiVirus)
They should be in a key called Implemented Categories, in a clsid key in HKEY_CLASSES_ROOT\CLSID\
Example, for AVG free: HKEY_CLASSES_ROOT\CLSID\{B64263D2-8A70-4f86-BC9A-57BE9A7B66DD}\Implemented Categories
2-Rename that Implemented Categories to something else
3-Repeat if you have multiple antivirus implementing it
4-Restart firefox
Your FF should now not have been able to find the interface, and should completly skip the scanning from now on.