I found the solution through a google search.

Guys,

I had the same problem and found the quick fix. It seems Windows has a limitation on how many of the same named documents it can save in the folder Temporary Internet Files/OLKE. Example, lets your fax.tif. You open up 99 of these named files in your lifetime, but on the 100th one, you get the outlook error, this is b/c Windows can only save 99 of these and the 100th one errors. It looks like this in your OLKE folder, fax.tif(97), fax.tif(98) and fax.tif(99). You have to go in and delete these so names files and then outlook can then start opening up those named documents again. BTW you cant just find the folder OLKE, you need to open up an old attachment in outlook and click on save as. In the dropdown menu where it saves “saveastype”, choose the correct format, ie. .tif files so it will show all of the .tif files located in that folder. Then you have to one by one delete them or at least the ones named as the same file that you are trying to open. Hope this helps.

Resolution:
In the registry find the following key
HKEY_CURRENT_USERSoftwareMicrosoftOffice11.0OutlookSecurity Value Name: OutlookSecureTempFolder Value Type: REG_SZ
Value Data: Temporary Internet Files

Copy the value to an explorer window, delete all files in the folder.
For Example: C:Documents and Settingsuser nameLOCAL SettingsTemporary Internet FilesOLK18F

Robert Creech provided this solution.