Answered myself (below)
I have two SSequencer props I need to merge together. I have an existing sequence that has been using a pixicon mega tree with the 16ccr graphic. I am trying to add another controller and prop, and I understand that Sequence Editor can only read one SS file.
I am attempting to merge them via SS. However, no matter how I do it i ALWAYS get a "Time length of file xxxxx is different than time length of file xxxx. Failed to merge"
I am using the exact same MP3 file. I have even exported each into a virgin Sequence Editor file, and manually verified the song length is 4m23sec. I still get the error.
There HAS to be a way to change the file times to match.
>>> I played with things for 3 hours before i searched for answers, then posted here.
I found the answer. I had to click on the very last effect in SS and check the time it was over. I then had to goto the other file and make sure its effect ended at the same time. That resolved the issue and allowed the merge.
So... next question.
this has to be a loophole to fix the issue. I cant imagine that an effect must continue on every merged file until the very end. For example, what if the singing faces end at 3m23sec, but animation ends at 3m 50 sec ?