Nevermind. I see Sergey pointed you to the cause of your problem...

Ok, in your original code, on what line do you receive the error? I'm assuming you have error trapping in place that catches that information for you?


>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.