I'm trying to update software and maps on my via 135. it connects fine, and then downloads for a few seconds, and then I get the "connect device to computer" message again. the computer icon on the tom tom remains. I disconnect the tom tom, connect it again, and it resumes the download for a few more seconds, and disconnects again. After about 15 "re-connects", I have 24% downloaded. I have re-installed MyDrive Connect twice. Suggestions?