Blackberry Dialup connection interupts wireless connection

I have my blackberry 7130e setup to be used as a tethered modem when I am not
at home, or work. But when I am using wireless, I keep getting taken offline,
and the dialup box keeps popping up to connect through my phone. I went into
internet explorer7 settings and changed my connection to "never dial-up" from
"dial whenever an internet connection is not present". I have been using this
for a while, but could this have been the issue?