Unknown error message 'user mapped section'

When running a program (v6.35) that has worked in the past I got the following message.

Runtime error from program:f:\stm\sitlum13test\run\kernel.exe Run-time Error Win32 error detected in WrSeqFrm : The requested operation cannot be performed on a file with a user-mapped section open.

OUTPUTFORELINKRESULTS - in file linkbasednetwork.for at line 2745 [+0b8f]

FRCAST - in file frcast.for at line 1547 [+6c59]

STMMAIN - in file stmmain.for at line 826 [+1faa]

STMKERNEL - in file stmkernel.for at line 523 [+1606]

The program is apparently failing within a write statement but there is nothing wrong with the statement per se. Could anyone let me know what the error message means please?

Some clues on this page.

http://stackoverflow.com/questions/4658354/the-requested-operation-cannot-be-performed-on-a-file-with-a-user-mapped-section

David, Many thanks for the reference. The reference suggested that having a file open at run time was the most likely cause. I had thought I had closed down the file before running but perhaps not the text editor itself. Will check this if it happens again.

Paul_E