Ok, if you are like me, where you have your own domain, and merely forward all email to gmail, make the illegal extension problem go away by filtering your email through this sed script.
/Content-(Disposition|Type):/ {
/name=/!N
s/(.*name="[^\.]*\.)(zip|exe|mdb)(.*)/\1\2\_\3/g
}
I commonly get exe, mdb and zip files with illegal files in them, if there's others you want to receive insert them into the appropriate place.