Oh. That's just a missing line I forgot to include in this post. I just abbreviated the code for posting. There is a SELECT MyId there.

>On what line do you get the error? Also, I cannot see how you replacing the field in the correct table:
>
>>use MyId in 0 alias MyId again shared <-- You open it in 0 not current work area why AGAIN and SHARED?
>>go top <--What table is currently selected here (and next lines the same question)
>>if rlock()
>> replace nextid with nextid + 1
>> nNextId = nextid
>> unlock
>>endif
>>use in select('MyId')
>>select (cAlias)
>>return nNextId
>>
>>Environment:
>>1. MyApp.exe runs on several MyAppServers. There are at least 25 instances of MyApp.exe running.
>>2. Data resides on MyDataServer.
>>3. At any given second, there can be at least 5 queries, updates or inserts (any or all) against MyTable.
>>4. SET REPROCESS TO 2
>>
>>
>>What preventive code should I put in - probably before the INSERT statement? I don't want to use the AutoInc functionality as the tables are before that version of VFP.