Had the same issue with OS X Lion.
Everything worked perfect and I had no issues with mounting drives, that were showing up on desktop as usual after upgrading from Snow Leopard to Lion. But after installing Paragon NTFS (v 7 or 8), disks did not only failed to show up, but they also refused to launch through disk utility.
Healing procedures at disk utility or Command+Option+P+R or checking the appropriate boxes in FINDER PREFERENCES did not resolve the issue.
Only thing that worked for me, was uninstalling the PARAGON NTFS, wiping out any leftovers in Library, and Installing Paragon V.9.5 which is designed to run with LION.