If you get an error when trying to convert a sequence, it would most likely be 1 of 2 things.
First of all, it must be an LOR 2 file, the converter will not convert LOR 1 files. To get a conversion from LOR 1 to LOR 2, you can download the demo version of LOR and simply open the file and save it agian, that will convert it to LOR 2.
Seconds, if it is an LOR 2 file, you have to make sure that the effects are only on, off, fade up/down, or set intensity, or it will not convert them.
I use the converter all the time because I found LOR before Vixen, and I like sequencing with LOR, but I like Vixen to run the show, and that is the best way to convert LOR files to Vixen.
If you need help converting things, shoot me a PM.