>Can anyone explain why I get an error if I try to create this index in VFP9 when it ran fine in VFP8 and earlier????
>
>INDEX ON UPPER(SUBSTR(cg_lname,1,AT(" ",cg_lname))+cg_fname)+loan_acct TAG coname

You've variable lenghth index key here but VFP supports only fixed lenght index keys. VFP determines the lenght of the key based on the current record at the time when INDEX command is issued. After index is created, if new index key lenght exceed existing key lenght, VFP9 generates an error because of possible index key truncation. The previous VFP versions silently truncated such keys. To avoid such problems, the index key expression should always return fixed lenght value. The PADR function could help with that. See http://fox.wikis.com/wc.dll?Wiki~IndexExpressionRequirements~VFP for more info.