This clearly shows that you are calling these entry points from within your program and it is not part of the COBOL run-time.
Were you linking in additional COBOL modules under NX 3.1 that you are now omitting?
Do you know in which module these routines actually reside?
Are you using the LITLINK or LITLINK"2" directive at compile time?
What does your cbllink statement look like under NX 3.1?