How to create mapping drives in Windows

I tried to create mapping drives in Windows NT Server 4.0, but it would not recognize the commands. Please help. Below is a sample of my login script.

ECHO OFF
net use z: /delete
net use z: \\server\directory
net use y: /delete
net use y: \\server\directory
net use m: /delete
net use m: \\server\directory

if “%username%” = “tran_quang”
then net use o: \\server\Folder
end

if %member% = “it”
then net use o: \\server\Folder\Subfolder
end