1201:   unable to find overlay file <filename> in current PATH

     Note:  This error can occasionally result from the effects of a
     virus.  In this case, first try external overlays (via the SECTION INTO
     xxx command) marking the .EXE read-only, and then follow the procedures
     outlined below.  If nothing else helps, perform an extensive check for
     viruses and take the necessary measures for removal.

     Explanation:  This message indicates that either too many files are
     open or that the external overlay file <filename> specified and created
     at link time, can no longer be found in the current directory or the
     current PATH.