If you're getting Connection Lock Timeouts or just generally poor performance with ColdFusion 5 using Oracle OCI drivers, here's why:
When ColdFusion 5 was being released, there was a bug in the Oracle OCI driver set that made simultaneous execution of multiple statements quite unreliable. (However, retrieving multiple resultsets could be done concurrently; this only applies to the time between when a statement is submitted for execution and when the first result row is available.) In the interest of stability, ColdFusion was made to single-thread it's access to that part of the driver; however, an undocumented switch was left behind for when that Oracle bug was fixed.
If you're running the OCI driver set, version 8.1.7 or newer, then you can remove this restriction.
The undocumented registry key that can be added to probably eliminate the "Oracle Connection Lock Timeout" and "Oracle Statement Lock Timeout" errors is:
Create this key and set it to a STRING value of "0" (zero) to remove statement locking. This feature is only available with ColdFusion 5, and the lock only applies versions of ColdFusion prior to ColdFusion MX. On Unix versions of ColdFusion 5, you need to stop ColdFusion, then carefully edit the cf.registry file to add this key to the correct place. (Or just use CFREGISTRY to add the key, then restart cfserver.)