utility will install or update the entries when the CICS is down.
is directly contradicted by the Resource Definition Guide
manual where section 4.1 states
The CICS system definition utility program, DFHCSDUP, is a component of resource definition online (RDO). DFHCSDUP is an offline utility program that allows you to read from and write to a CICS system definition (CSD) file, either while CICS is running or while it is inactive.
So you need to contact your site support group to get the CICS expert to determine whether your problem is specific to your site, or if the problem is something specific to your job.