Are you sure it's not indexed? If you goto to SQL Mgmt Studio, there should absolutely be an index called KNAME with columns VendorName + APVendorNo + VendorNo. Also in the Profiler trace if the pvx program / line points to a pvx SELECT or READ stmt, there should be a KNO=""KNAME"" clause in it. It sounds like that is already the case since Brian said ""ORDER BY [VendorName] , [APDivisionNo]"".
If index is in fact physically missing then have Brian run this while in the correct database:
CREATE NONCLUSTERED INDEX KNAME_AP_Vendor ON dbo.AP_Vendor
(VendorName ASC, APDivisionNo ASC, VendorNo ASC )