For IDMSINFO to initiate cleanly, CAIRIM must have already been run to install the r18.5 SVC and related APF modules using GJI5INIT.
When CAIRIM installs the r18.5 SVC using GJI5INIT, GJI5INIT will load several modules from the r18.5 APFLIB in addition to the SVC.
These modules are RHDCSSFM, IDMSMSVA, CAIXDOA$ and PMRTDATA. This last one is a new module since r18.5.
PMRTDATA contains the IDMSLPAR DSECT, which IDMSINFO requires.
If PMRTDATA has not been loaded into the LPA by running CAIRIM, IDMSINFO will get the DC130051 error.
For CA IDMS r18.5, make sure that the PMRTDATA and GJI5INIT modules are at PTF level RO71145 or above. These PTFs are required to make IDMSINFO work properly. If any of these modules is from a lower PTF level, even after a successful CAIRIM run, the DC130051 message will keep appearing.
The above mentioned PTFs are NOT required for r19.0 because they are included in the base release.