When using the scrolled text it is important to remember that a line needs to be painted in full before it can be scrolled out. Therefore sometimes it may cause the delay. It usually happens if too large font or text effects are used. Unfortunately these results from the limitations of the CD+G format and some of the algorithms used to generate the text. We have some ideas how to improve scrolling mode and will probably do some work early next year.
And about cdg2avi — I think it might be an error in cdg2avi software. A lot of software CDG players do not handle scrolls properly (another one that has problems is DART CDG Player). And I am afraid there is no way around — the PowerKaraoke-generated scrolled-text mode songs play correctly on hardware CD+G players, and this proves they are created correctly. But the good news is that in late January or early February we plan to release an add-on that will allow to generate AVI files from PKD documents resulting in high-quality (much better that CD+G) VCD source.