[App_rpt-users] Zaptel directory goes missing on node

Hi All, I'm posting this on behalf of a friend Eric VE3EI that has 2 nodes. He has 2 nodes that are simplex and have Chan_IRLP anf Chan_Echolink. The problem he has is the nodes seem to work fine for a few weeks then, for some reason the Zaptel directory seems to disappear from these nodes. Now Asterisk goes nuts because it cant find the Zaptel drivers. I have not seen this on any of then nodes I have so I'm at a loss as to what is going one here. He is using the normal ACID distro and nothing different. This is the 3rd time it has happen on one node and has happened on the other once. Each time he has done a complete reinstall to fix it but it still seems to occur. Any ideas on what may be wrong?? Thanks, Jon VA3RQ