Forms :: Access File From Server Via Static IP At Outside LAN

I am using oracle 9i release 2 and forms 6i.I have a question,I have stored all the fmx files under one folder in a single server called "MAINSERVER".From here only client system calls the forms.In am calling forms in call_form function like

call_form('\MAINSERVERFORMSemployee.fmx',no_hide);

here mainserver is the server name, forms is the folder name and employee is the form name in fmx format.My question is when i call form from server with in a network no problem but When i call form from outside lan that through internet via static ip forms are not called.I tried like this way call_form('\198.52.67.66FORMSemployee.fmx',no_hide).Here i have specified static ip and forms folder but is not working.