I also have this problem , mainly when using NetX the button sticks and the light on NetX remains green until it finally loses connection altogether.
I have equipment in cupboards and it has now got so bad I have abandoned the NetX and am using Powermids via IR on the Ipronto which kinda defeats the object of WIFI capability and wasted over £600.
I have been having this problem for some time , cannot remember exactly when it started but I know it was shortly after I changed my Router from 802.11b to b/g in mixed mode so maybe it is that.
Interestingly I have 2 Ipronto and 2 NetX and the problem occurs in any combination.
My NetX will not work for differing lengths of time after a sticking problem.
Please let me know if u have any ideas.