After installing IE7, I found that clicking on a web link in a document on Outlook 2003 resulted in a prolonged wait followed by a “Locate Link Browser” error.
This problem prompted me to call the support number, 1-866-234-6020, listed on the IE7 site, where a polite Indian gentleman told me he would have to charge me for any IE7 assistance. He did suggest that I revert to IE6, which I did, and now all is working fine again.
Perhaps IE7 is not yet quite ready for general use.