Windows XP SP3
Internet Explorer 8
Outlook 2007

All of a sudden, whenever I click on a link in an email in Outlook I get a
popup that says:
General failure. The URL was:
URL The system cannot find the file specified.

But Internet Explorer opens the link successfully.

The last patch applied to the system was:
Cumulative Security Update for Internet Explorer 8 for Windows XP (KB978207)

This was applied late Friday and the machine was not used on Saturday.
Today, Sunday, the popup started.