Internet Explorer hangs on Import and Export screens

I'm running CivCRM 1.2 on Drupal, and it's working very well. However, there are two screens which cause Internet Explorer to hang. It will not respond unless I manually shut down the program.

First is the import contacts front screen. If I click on "Import Contacts", it will go to the new page, then just hang indefinitely. I never get to choose a file or specify any other details - the form does not come up.

Second is the Export option in the drop down menu on the search screen. If I search for a group of users and choose Export, the same thing happens. A new page comes up and then just hangs with no additional response.

Any ideas for resolving these issues?