scanner + event handlers

Vista ultimate sp1, epson v350 scanner.

To get the scanner buttons to work properly I need to set them up via contral panel - hardware - scanner - properities - events.

However when I set button a to open program b I get error “the attempt to change the registered event handler failed…” .

looking at other forums this seems a common problem but no advice offered.

Please help

Hey guys when I try to install Hp scanjet 4070 image Zone software I get this message.. If there is any other software that I can use please let me know in advanced thank you so much!

OS Version: Microsoft Windows 7 Home Premium, Service Pack 1, 64 bit
Processor: Intel(R) Core™2 Duo CPU E4500 @ 2.20GHz, Intel64 Family 6
Processor Count: 2
RAM: 6143 Mb
Graphics Card: NVIDIA GeForce 9800 GT, 512 Mb
Hard Drives: C: Total - 172469 MB, Free - 33523 MB; D: Total - 99998 MB, Free - 85451 MB; E: Total - 49999 MB, Free - 45468 MB; F: Total - 49999 MB, Free - 49892 MB;
Motherboard: ASUSTeK Computer INC., Berkeley
http://i.imgur.com/C5SYm.png