Here are the SET-parameters you need to modify:
(the default values are for NW4.11)
Maximum Record Locks Per Connection (default: 500, range 10 - 100000)
Maximum File Locks Per Connection (default :250, range 10 - 1000)
Maximum Record Locks (default :20000, range 100 - 400000)
Maximum File Locks (default: 10000, range 100-100000)
A rule of thumb is to double the parameters and monitor if the problem persists.
This means if parameters were set at default, the parameters should be changed at the server console to:
SET Maximum Record Locks Per Connection=1000
SET Maximum File Locks Per Connection=500
SET Maximum Record Locks=40000
SET Maximum File Locks=20000
The parameters can be set in startup.ncf or MONITOR.NLM/SERVER PARAMETERS to make these changes permanent.
Good Luck!