Hello, can you tell me what is the solution for this problem. we have the same error on our environment.Thank you 

X3AFRICA,

The solution for us was to change the Sequence Type from NORMAL to GROUPED for our Work Order Sequence numbers. You can do this in v7 through the SETUP > GENERAL PARAMETERS > SEQUENCE NUMBER DEFINITION > STRUCTURES links. This opens the Sequence Number Definitions page. You can find the sequence number causing the error and change its Sequence Type. You can find a description of the 3 sequence types in the Function help page for the page. 

Since we've adjusted our work order numbers to grouped, we haven't had any issues with this kind of error. We have started having it with our Stock Change sequence number and are looking at changing it's type as well.

This is a very good suggestion.

This is referenced in the knowledgebase using the error "Error: "The data that are being updated are locked by another user (Locking Error on Table AVALNUM) Do you want to try again?" (KB ID 47171).

There is much more detailed information (and considerations) about the sequence counter types in the online help topic "Supervisor - Structures" which is a reference to Setup >  General parameters >  Sequence number definition >  Structures , where you would make the decision and change.

I tried your solution (change the type of sequence) but in vain always same problem.
I do not know which number to set in the field "NB number"? do you have an idea

From the Function Help:

So if you use Grouped Sequence numbers, this field sets the size of the group. If you want 10 sequence numbers to be created as a group and used as needed then you would put 10 here. If the field is set to 0 then no sequence numbers will be created.