can't save Mp3

I installed WavePad and downloaded the extra component for mp3 saving.

I load a wav or mp3 file and make some edit, but when I choose 'save as' and mp3 it

connect again to internet to download again this component, it says it is installed ok

but then it says it can't save the file in mp3 format.

I installed also the component mp3 manually, but the same result...

What is this?

TIA

I foun out the problem: I was'nt logged in as Administrator.

Now it works, but I have another question:

I open a mp3 file and the after simple cut I want to save again to mp3

WITHOUT recompress it.

Is it possible or every time I press 'save as mp3' the wave is recompressed?