I'm reading these through WAY after the fact but I've got both a VS-100 and an A-PRO300 and haven't had any of these problems.  Part of the problem may be that folks are running the installers or launching Sonar with Admin level privleges?
As far as the A-Pros go I agree with many many others who have pointed out that the included and the available online documentation for these units absolutely suck!  I have to wonder whether Cakewalk or Roland outsourced the job of writing the A-Pro guides to the staff at Behringer.  I've purchased a LOT of midi hardware over the years since I purchased my first Cakewalk software and up until now I'd nominate Behringer for the absolute worst documentation and tech support I've ever seen. (I've been a computer/network technician for over thirty years)  If it wasn't for a giving person on this forum named A.J., my BCR2000 would have shared the same fate as the laser printer in the movie "Office Space."  (I sent him a small donation but his help exceeded the value of the unit itself.)  There are some brilliant people on these forums!

You should check which control surface you have the A-300 using. THere's 2 of then. 0-19 different layouts but only 0 and 19 are the dedicated Sonar settings. I always use 19 becauswe it works. There are some great threads about set up so do a search on configuring a-Pro controllers. I seemto recall deleting the control surface settings and then building an new one based of A-pro using the #19 conrol surface option.

After my coffee I may have more to say. Good luck

Hi - new A800 owner here - I am having exactly the same problem - just spent all night trying to sort it - really frustrating - followed the suggestions on another thread but that got me nowhere as well!

Shortly after writing the above I realised that I should have installed the 32 bit version of the control software with Sonar LE. Seems to be working now - though I imagine I will be back for more advice along the line!

Not sure why, but my options have slightly different values to yours. In MIDI inputs I have > A-PRO, MIDIIN2 (A-PRO), MIDIIN3 (A-PRO). In MIDI Outputs > A-PRO, MIDIOUT2 (A-PRO). IN order to get the ACT Control Surface to work, I have to select MIDIIN3 (A-PRO) as the input.

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