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This thread has been moved to the Pioneer DVD recorder & player forum as this sub-forum specifically covers these.
I can understand the freezing issue if you use "Frame Accurate Editing", however I'm not fully sure why it would stick when skipping over a cut-out section using the "Video Mode Compatible Editing". If you choose the "Frame Accurate Editing", when the title plays back up to the point of the cut, the DVD recorder needs to jump to the keyframe before the frame it is suppose to resume from and decode the frames up to this point before it resumes playback. If there are several frames from the keyframe up to the frame where the cut ends, this can result in a brief pause. However, if you choose "Video Mode Compatible Editing", what this does is cut the video at the actual keyframes, such that when the player skips over a cut-out section, it does not need to decode any frames leading up the resume point in order to begin displaying the picture.
Just in case it has something to do with hard drive seeking when it reaches the cut-out point, I would recommend trying to copy an edited title to a rewritable DVD to see if it sticks at the cut-out points when playing back the DVD. If it plays back without a flaw, then it seems like the DVD recorder takes a bit of time to seek the next point when playing back from its hard drive.
Unfortunately, it is not possible to join recordings on the hard drive with this Pioneer model, whether they are two splits of what was originally a single recording or two different recordings. Only some brands of DVD recorders allow the combining of titles, such as the Lite-On series of HDD+DVD recorders.