Hello Dennis,
I think this parameter has limited connections to the enqueue server. In the warning you see:
no more free handles (1011)
1011 - number of used handles
You need to increase the value for enque/server/max_clients. How many work processes has the affected system? As per note "2013043 - Performance Problems with Enqueue Work Process" this value should be at least the same as total number of the work processes in the system. You may need to check also other enqueue server parameters as described in this note.
Regards,
Alwina