Rather than using the SQL Server lock table the application uses the Vision lock file which is specified in the configuration variable A_MSSQL_VISION_LOCKS_FILE. When the program runs it crashes on the first attempt to open a SQL Server table. This is seen in the trace file:
opening data segment (#0): Lock4GL.dat
Alt lockfile [Lock4GL.dat] error 1
The configuration variable A_MSSQL_VISION_LOCKS_FILE must be set to include the complete path and file name. In this case the path was omitted and it specified only the file name. Adding the path to the file name will resolve the error.