File locking on a network

We have a mixed environment of Intellicad and Autocad LT on our small W98/ME network. Sometimes, Intellicad does not properly "lock" the file when opened on the network, allowing other users to open, without warning, a file to which they should not have access. I am not sure if this is a pure Intellicad bug or a mixed W98/Intellicad bug. A file is generally locked for a time after it has been saved, then the lock is (sometimes) mysteriously lifted. Loss of data is very often the result.We have devised a (hopefully temporary) fix for the problem, by simulating the Autocad .dwk files. Autocad no longer produces .dwk files, but fortunately still recognizes them as lock files. If anyone else experiences similar problems, use this method.;Copy & paste to Icad.lsp;from here (xload "doslib4.dll")(command "undefine" "open")(command "undefine" "wclose")(defun c:open ()(setq new_dwg_name (getfiled "Open drawing" "" "dwg" 4))(if (or (findfile (strcat(substr new_dwg_name 1 (- (strlen new_dwg_name) 4))".dwk"))(dos_openp new_dwg_name))(alert "The drawing is locked!")(progn(setq file (open (strcat(substr new_dwg_name 1 (- (strlen new_dwg_name) 4))".dwk")"w"))(close file)(command ".open" new_dwg_name))))(defun c:wclose ()(dos_delete (strcat (getvar "dwgprefix") (substr (getvar "dwgname") 1 (- (strlen (getvar "dwgname")) 4))".dwk"))(command ".wclose"));to hereThis requires doslib4.dll in the intellicad search path to work. If you don't have it I can send it to you. A drawback is that the handy last files shortcuts in the File menu will no longer work. Not a big sacrifice to make for drawing/network integrity. Also remember that the .dwk files must be deleted manually if Intellicad crashes (like Autocad in the old days). This lisp workaround does not support any other method than WCLOSE for exiting a drawing. This means typing wclose or closing the drawing with the upper right "X" of the drawing window (NOT the Intellicad main window). Other methods such as EXIT, QUIT or WCLOSEALL are not supported.