I have a Avanti dryer and after its on a few minutes it also cuts off. Can you tell me why or what to do to fix this problem?

Maybe the thermsistor needs replacement. The thermsistor is a safety device that prevents the dryer from overheating. If high heat is detected (or the thermsistor is defective) the dryer will turn off.
Maybe you have a clogged exhaust port. This will impede air from exiting causing overheating and cause the thermsistor to "trip" and the dryer will stop.
If there is no clog and no air is exiting the exhaust vent you probably need a new BLOWER FAN belt.
instructions here:
http://avantidryer.weebly.com/store/c1/Featured_Products.html

See this causes and fix it. God bless you
Timer
The timer could be the problem. To check this, turn the timer to a timed cycle say 30 minutes or so then time it. If in 30 minutes the timer hasn't moved and the dryer is still on, the timer is bad and needs replacing. If in 30 minutes the dryer is off, the heating element is your problem

Heating Element
This is the most likely cause for some dryers timer not advancing. Some dryers have two heating elements and if one goes out the timer will not advance if you use it on an automatic cycle but you will still feel heat inside the tub.Replace the Heating Elements