EDIT - Information about error return codes (though not sure how useful it can be):
4 internal mount bug
115 = 64+32+16+2+1
1 incorrect invocation or permissions 2 system error (out of memory, cannot fork, no more loop devices) 16 problems writing or locking /etc/mtab 32 mount failure 64 some mount succeeded
EDIT: Care to explain how is the VPN connection involved?