Using the Konsole - by a complete Linux newbie!

[Madeleine Rollason]

I'm a student with the Open University here in England, and need to use 
XAMPP for my studies, I have tried several times to download and install 
it through the Konsole with no affect.  It gets saved to my desktop as a 
tar.gz file.  I get the following message whenever I try to untar it to 
the correct place as specified by Apache Friends - help please!
'Error Message:' (I have placed x's where my name should be)

root at xxxxxxxdesktop:~# tar xvfz xampp-linux-1.6.2.tar.gz -C /opt
tar: xampp-linux-1.6.2.tar.gz: Cannot open: No such file or directory
tar: Error is not recoverable: exiting now
tar: Child returned status 2
tar: Error exit delayed from previous errors
root at xxxxxxxxx-desktop:~#
root at xxxxxxxxx-desktop:~#
root at xxxxxxxxx-desktop:~#

any help would be greatly appreciated
Maddie