got back to using my guitar amp and effects ect. from just playing guitar through guitarport..

plugged in my dime wah.
worked for a minute or so. all the signal cut out & now getting a mass of distorted noise. only when its clicked over onto the wah.
clean, there is no problems
running it off a 9v ac adapter,

does anyone know what it could be that is causing it to happen??

You want to make sure that power adapter is outputing 9v DC and NOT 9v AC. If it's AC, you fried some stuff.