I have been trying to run a code (far too long to include here) which includes the line:     swath_id    = EOS_SW_ATTACH( sw_id, swathname[swath_ctr] )     n_fields    = EOS_SW_INQDATAFIELDS( swath_id, field_list, rank, n_type ) I have been running a loop over the entire thing so that I can process all the files in my directory .  So far, every time i run the code after 30 runs of the loop, the code crashes because sw_id returns -1, and therefore n_fields returns the following error: EOS_SW_INQDATAFIELDS: Unable to query (null) information. I am wondering if anyone else has experienced this or knows what might be causing the problem? Thanks.