How can I put my themes from one psp to my friends?

I have a new PSP Premium Theme and when i put it on my friends it says: The copyright protection is invalid. (80108355) How can i put it on his? We both have CFW.
ITS A PREMIUM THEME FROM PSN!!!

depends on what kind of theme it is? PTF, Flash0, RCO, CTF
(one quick note, make sure the theme works for his version this might be the prob.)
if its a:

PTF:
1.plug in your psp to your computer
2.Go to PSP> THEME
3.copy and paste the "theme" to your computer
4.copy to your friends

CTF/RCO:
(first off for these themes you must find the CXMB for your version, depending on what your version is go to google and type in 5.00M33 CXMB for example)
-after you have the CXMB on your psp then you can install the theme
-the CXMB should come with instructions on how to install (simple)
1.(make sure both you and your friend have the same version and CXMB)
(this explains how to install a CTF/RCO)
1.copy the CTF or RCO theme to PSP> THEME
2.turn off your psp
3.turn it back on while holding the R button go to "plugins"
there should be a file named CXMB enable it and exit.
4.you should now be able to use your Themes

Flash0:
1.press "select" on your psp (NOT while its plugged in)
2.the option that says "USB Device" should be switched to flash0
3.plug it in to your computer and copy all the folders where they are suppose to go,. overwrite them

In future refrences i would post your PSP model and version in order for us to help you better