Has anybody had this error with Excel?

I'm trying to help someone in one of our branch offices with a MS Excel spreadsheet. It has a number of web links. When my user clicks on any of her web links, an error message pops up: "An unexpected error occurred." Has anyone had this problem before? She's running Excel 2003 and IE 7 on Windows XP.

I had her email the same sheet to me and it works OK on my machine (I'm running Excel 2002 and IE 7, however). I already checked and verified that IE 7 was set as the default browser. We even tried copying the web links from one spreadsheet and putting them in another. This didn't work at first, but I had her restart her machine, and the copied web links in the new sheet worked ok, but the old sheet continued to misbehave. We'd just go with a new one but that old sheet has a truly extensive amount of charts and other data in it.

I'll certainly give it a try, but my user tells me that it was working fine up until recently. I'll take a look at the spreadsheet though and see if there's anything that's embedded.

I've only been able to replicate this error when the hyperlink is a reference to another cell; it has worked fine on my machine, but not my user's machine, if the hyperlink is to a website.