I have observed what I consider to be a bug in VFP 6.0 SR4 that generates "Alias not found" errors from time to time. What I have found is that for some reason the alias name for my table ends up as the full path string. In other words, if I do a DISPLAY STATUS and look at the alias name for the table, instead of showing up as the 8 digit name it should be, it displays the full path from the drive letter on up. When I try to select by the correct alias name it generates the ANF error. I have tried everything I can think of to duplicate this condition but have not found a way. Below is an actual capture from my error log:

Current Database: G:\CSIUAPPS\CSIU\MTVW\DBF\STDSYS.DBC
Select area: 10, Table in Use: G:\CSIUAPPS\CSIU\MTVW\DBF\HEA\HE_PARMS.DBF Alias: G:\CSIUAPPS\CSIU\MTVW\DBF\HEA\HE_PARMS.DBF
Code page: 1252
Structural CDX file: G:\CSIUAPPS\CSIU\MTVW\DBF\HEA\HE_PARMS.CDX
Master Index tag: HM_BLDG Collate: Machine Key: HM_BLDG Candidate For: .NOT.DELETED()
Lock(s): Exclusive USE

The alias name should be he_parms but as you can see it ends up being the full path. Is it possible this is happening for you as well or are you seeing just the alias name itself?