Hi Steve,
The way the Library loader was originally designed lends itself to issues with some large collections. I've improved it quite a bit but had to stay within the limits of the original design. You may have to use the Browse panel to select music, or an external app like MPoD...
Andreas, the fellow who is working on Moode 3 project has redesigned the Library loader so it will work nicely with large collections but Moode 3 project will probably take a year to complete since it involves a ground-up rewrite and debug of the entire code base :-)
Regards,
Tim