The following sequence of messages are seen during startup:
DC013004 Vnn T0 ATTACHING DRIVER FOR LINE UCFLINE
DC027006 Vnn Txx TASK:*DRIVER*; RECURSIVE ABEND.
LINE DRIVER ABEND
Then the CV fails with a U3970 abend. The dump will show there was a S0C4 in module RHDCD0ZU at offset 238.
This is caused by the UCF system table RHDCFSTB not having the correct entry point specified. If you re-assembled the UCF system table check the END card, it should have the label of the #FESTDEF macro. There is an example of the code in page 240 of the System Operations manual.
There is also an SMP/E usermod in the SAMPJCL library in member UMODFSTB to make changes to this table. This member has the table source as well. The provided source uses the entry point name of FESTABLE. It should look like this:
FESTABLE #FESTDEF CNT=17
The problem could also occur if you use the IBM Binder to create an alias of the load module but do not specify the entry point. You can specify the entry point when creating an alias like this:
To create an alias called FSTBSY20: