Commands like 'ls', 'cd', etc. are Unix specific (Linux, FreeBSD, SuSe, etc.). You can use the exec and system commands, but you need to "windowize" the command that you are running. For example the 'ls' command is the same as the 'dir' command in windows.

For example:

is equivilant to:

In regards to being able to use these commands, make sure that safe mode isn't enabled and that you have permission to perform the commands.

It will be easier to go to "Start => Run => Type 'cmd[enter]'" For the command prompt you will be able to test out commands, then just type those into the exec command.