Compressor belt dies on HIGH RPMs

Hey
There's my Story....
I bought a "dodge caravan 96" about 7 months ago with empty AC system.
So it getting hot, and I decided to fix it.
I found/repaired a leak.
Vacuum system to 500 mic.
Charged with 2.16 lb of 134a
AC works just fine while engine is idling, but if I will increase RMPs the compressor seizing up and burns a belt.
Anyone has any thoughts on this subject?

My own thoughts:
Clutch, but if clutch will get seized it should stay engaged with compressor!? isn't it?
Compressor, but why it works on low RPMs?
Maybe the scale was out of calibration and I overcharged the system? Again, why it works on low rpms?

NOTE:
idler pulley- OK

When you recharged the system did you add a can of refrigerant that contained compressor oil. If not the compressor is probably heating up and seizing at higher rpm's. If you added this you may have to replace the compressor due to internal damage.

Thanks for the quick reply.
Nope. I didn't add any oil into the system.
I didn't replace any parts and I had a leak on the high side which didn't have an indication of oil leak.
So I was assuming that oil level is still ok.
Another thing, it seizing up as soon as I increasing RPMs, even if I just started the AC and compressor is still cold.
Cheers,
Will be glad to hear more of your thoughts.

Let's see... I just installed a new compressor in my 96 caravan and it did the very same thing. It looked like the clutch was bad but it turned out to be the belt. Evidently the parts shop lists a thinner belt than is required. I took it to a good mechanic in queens and he did a detail test. Usually the problem would start the next day after installing the belt. Since he put in the bigger belt about 1 week ago i am yet to experience this problem.

Worth a Shot.