1. run command modprobe opvxd115 to check if can find driver opvxd115,if can't ,you should reinstall dahdi driver.
(before reinstall,remember to delete previous driver directory, it maybe /lib/modules/`uname -r`/dahdi or /lib/modules/`uname -r`/weak-updates )
2. you can add my skype(dario.hu2) and prepare teamview. i will help you to check it out.