I have done everything as you said but i am not able to create a profile or desktop shortcut....
Here is my cheat sheet for your review; maybe it will help you:
firefox.exe -P My Profile -no-remote
"C:\Program Files\Mozilla Firefox\firefox.exe" -p 2nd-copy -no-remote
"C:\Program Files\Mozilla Firefox\firefox.exe" -p 3rd-copy -no-remote
"C:\Program Files\Mozilla Firefox\firefox.exe" -p 4th-copy -no-remote
"C:\Program Files\Mozilla Firefox\firefox.exe" -p 5th-copy -no-remote
Now I'm not sure where your FireFox is located but I run XP flavor OS (XP, Win 2k3) so these work for me. You might need to change the path.
Now run the first line in Windows (Start, run and copy paste "firefox.exe -P My Profile -no-remote" in the box without the quotes and click Ok or hit Enter)
Box pops up and click create profile, follow steps and name 2nd-copy, click finish and create another profile, name 3rd-copy and so on.
I gave you 5 links there for your shortcuts. Here is how you use those.
To use those shortcuts, right click on your FireFox desktop Icon and left click properties, click find target and on the FireFox.exe right click and send to desktop new link.
New desktop FireFox icon will probably say copy of FireFox or similar. Now on that copy of FireFox icon just right click and go to properties and left click You should be on the target tab, copy and paste that first link I gave you:
"C:\Program Files\Mozilla Firefox\firefox.exe" -p 2nd-copy -no-remote
in the traget box and then click the General tab and in the top box name your 2nd profile whatever account name you want it to represent. Click Ok.
Now when you double click that icon on the desktop you're opening a new profile that is separate from the original.
Now if you made 5 of these when you ran the create profile module, just close that 2nd instance, now on desktop just click once the 2nd copy icon and right click and select copy (Ctrl + C), now Ctrl + V to paste 3 more on the desktop. Now right click each of those copies, go to properties and drop in the other shortcuts I gave you and rename those instances to account names.
Now you have 5 profiles all unique and isolated from each other. Install whatever plugins you like to run on each, set a proxy on each and you're good to go.
I might of missed something as I did this all from memory but that should get you headed in the right direction.
Good luck.