A member of a PDS is just a sequential file. You can have as many duplicates as you want.
In what way did DISP=OLD not work?
You need to learn how to look up messages, abend codes and things like that. Even if you google for Abend SE37 you'll find the information you need.
If you are putting lots of data into a member, and it is a PDS not a PDSE, you will get quite regular space problems. If you don't know anything about compressing a PDS, including making a back-up of it first, then get in touch with someone at your site who does, and seek their assistance. In a PDS, when a member is created, the space previously referenced by that member is just abandoned, to be recovered later by a compress. PDSEs recover the previously used space as they go along.
Maybe while doing your testing with bulk data, just use a plain sequential file, not a member.