COBRT096 Invalid use of fork() (Fatal)
You have called the operating system's fork() API in a process that has called COBOL functionality, or has multiple threads, and then called some COBOL functionality in the child process.
COBRT099 Illegal operation in SORT/MERGE module (Fatal)
A SORT or MERGE module has received a RELEASE operation outside the Input procedure, or a RETURN operation either outside the Output procedure, or before the Input procedure has terminated correctly.
COBRT100 Invalid file operation (Fatal)
You have tried a file operation which violates a general rule of COBOL in some way. The most likely cause of this error is that you have tried a rewrite on a sequential file opened I-O, or on a relative file with access mode sequential also opened I-O, without preceding it with a successful read NEXT.
