Arbitrary code can be executed on the remote host through Microsoft Excel.
The remote host is running a version of Microsoft Excel that is subject to various flaws that may allow arbitrary code to be run. An attacker may use this to execute arbitrary code on this host. To succeed, the attacker would have to send a rogue file to a user of the remote computer and have it open it with Microsoft Excel.
Microsoft has released a set of patches for Excel 2000, XP and 2003.