SQL Server 2012 Unable to Utilize Defined Amount of Locks
Is there any trace flag enabled or any tweaking into startup parameters of SQL server can you please check that.Have a look at below Microsoft support article

http://support.microsoft.com/kb/2199576/en-us
Keep max lock value to default 

EXEC sp_configure 'locks', 0 ( I guess you tried this option already)

Now if you face this issue again best possible workaround will be to decrease the amount of rows being transferred. Every lock has memory associated with it so if there is lock contention I believe its somehow related to SQL Server buffer pool memory. Did you run DBCC MEMORYSTATUS and check value for

OBJECTSTORE_LOCK_MANAGER (Total)       KB 

please do tell us what is value of single page and multi page allocator for above clerk