The new g-groups.wisc.edu interface no longer has problems accepting which email you are subscribed with.
There's no need to subscribe with a different email address, unless you want to change to using something that is NOT a UW address, such as a gmail account.
to subscribe to a list-serve without using your wisc.edu address, simply email the list and add a +join after the name but before the @g-groups.wisc.edu.
For example:
analysis@g-groups.wisc.edu
If you want to join the Analysis list, email to analysis+join@g-groups.wisc.edu.
If you want to leave the Analysis list, email to analysis+leave@g-groups.wisc.edu.