I just installed a version of knoppix 3.4 to my hdd, now I'm facing a very anoying problem.

I'm not able to choose any other partition to save my stuffs.

Example:
I wanted to save a webpage, so in Mozilla I go file-->save page as
and a save as window will popup with /home/yuanlong/desktop
I have my drive mount to /mnt(actually knoppix mount them automatically)
so I went to search for /mnt.
But everytime when I double click on the /mnt the whole programe would hang and I have no choice but to force shutdown the program. This applies to alotz of other programs

So is there any way I could fix this? And sorry if this is a easy one as this is the first time I'm using linux.