CompuServe Messages

Has anyone here experienced this problem and/or have a solution? I recently bought the Studio16 3.0 upgrade from Sunrize and I have been using the program for a few weeks now. First of all it is terrific, even the manual. I am making the sound track for a 50 minute video, using only two tracks. I am using LTC SMPTE to trigger the CueList. I am experiencing a drift where the sound comes in increasingly earlier, and by half way through, the sound is too early by over 2 seconds. The amount of the error would seem to be related to the difference between dropframe and non-drop frame timecode. I have checked out everything many times, restriped my tape to make sure I was using non-dropframe code, and had discussions with tech support at Sunrize, and so far no solutions. I have been working on resolving the problem for several days now, and I am getting frustrated. Manually altering the CueList to make allowances for this is tedious, because it is an exponentially multiplying error and must be done from the beginning through to the end in gradual increments. Fortunately I am not doing matchframe editing, but still it is a serious problem. Any help or advice would be much appreciated.