Data Area Locking

We use a data to maintain an unique ID number - Application RPG programs
call a dedicated RPG program that uses the data area to generate a new ID.
The RPG program to generate the ID uses the data area in the following
manner:  1.) retrieve the data-area to import the current ID number 2.)
increment the current ID number by one to generate a new ID and 3.) update
the data-area for the new ID number 4.) release the data area.

On occasion we get the following sequence of messages when the RPG program
that locks the data-area is unable to execute the IN operation against the
data-area:
MCH5802       20     Lock operation for object &1 not satisfied.
RNQ0431       99     Data area &6 was allocated to another process (C G D F)
        
The RPG program will go into MSGW until the RNQ0431 message is answered.  I
have tried to use the Error Indicator and Error extender on the IN operation
to prevent the message wait state be no such luck.  What can I do to prevent
the programs from going into the message wait state when unable to allocate
the data area?  I thought using the error indicator/extender on the IN
operation would prevent the MSGW; much like what happens on database file
I/O operations.

Thanks,
Keith