The 3003 indicates the DMCL definition and the physical file do not match as far as Page Size or Page Range for the area in question. Whenever IDMS reads a requested page we check the page number in the header to be sure it is the page number expected based on the AREA definition included in the DMCL. If that check matches, we then use the Page Size defined in the DMCL to find the Footer of the page and check the page number again. If either the page number check in Header or Footer fails you get 3003. Execute an IDMSLOOK on the DMCL using the ALL option, and check that it has the correct page size and page range.
There are several possible reasons to receive abend 3003 The DMCL could be correct but the DSname accessed is not the correct file or it has not been correctly FORMATted with the correct DMCL. The physical area/file is correct, but the DMCL is incorrect as far as page range, page size or DSNAME