In User Prefs try unchecking “Abort capture on dropped frames.” Also, in Log & Capture you can try changing the Device Control selection to Non-controllable Device in the Capture Settings tab and using Capture Now instead of logging.
Has L&C ever worked with this machine and a different tape? If so, there probably is something wrong with the tape, perhaps bad timecode, control track or dropouts.
It never hurts to trash prefs and repair permissions.
John
MacPro 8-core 2.8GHz 8 GB RAM OS 10.5.5 QT7.5.5 Kona 3 Dual Cinema 23 ATI Radeon HD 3870
ATTO ExpressSAS R380 RAID Adapter, PDE Enclosure with 8-drive 6TB RAID 5
24″ TV-Logic Monitor
Final Cut Studio 2 (up to date)
Pro Tools HD w SYNC IO, Yamaha DM1000, Millennia Media HV-3C, Neumann U87, Schoeps Mk41 mics, Genelec Monitors, PrimaLT ISDN