When you try to download the OAB from Outlook you may receive the following errors:

0x80190197

or

0x80190194

There are several reasons for this, see the following articles:

http://technet.microsoft.com/en-us/library/dd285503(EXCHG.80).aspx

http://blogs.msdn.com/dgoldman/archive/2006/11/27/Error-0x80190194-when-using-an-outlook-2007-client-to-download-a-web-distribution-enabled-oab.aspx

http://blogs.msdn.com/dgoldman/archive/2006/08/26/725860.aspx