When you have errors, ALWAYS post the code causing them as well otherwise we have no idea what the processes are. A likely cause is you have run out of disk space for the dataset or it has been corrupted in some way.
This points to a damaged dataset file. The information stored in the first page of the dataset file points to more pages than the file actually contains.
This can happen when you run out of disk space while writing to a dataset, or if some kind of data transfer/copy terminated prematurely.
If the dataset in question was created by an earlier step of the same program, read your log from top down. The most important message (ERROR/WARNING or unexpected NOTE) is always the first one, the last one is least important. Fix the first issue, and all others might already go away also.
If your dataset comes from other code, read that log(s).