Look at line 384 of the GlueParent.xml. What is being called? Is it using class data? If so where is it getting that data from? Does that contain the data for your custom class?
Most likely you are missing GlueAmbienceTracks data:
Code:
GlueAmbienceTracks = { };
GlueAmbienceTracks["HUMAN"] = "GlueScreenHuman";
GlueAmbienceTracks["WORGEN"] = "GlueScreenUndead";
GlueAmbienceTracks["ORC"] = "GlueScreenOrcTroll";
GlueAmbienceTracks["DWARF"] = "GlueScreenDwarfGnome";
GlueAmbienceTracks["TUSKARR"] = "GlueScreenDwarfGnome";
GlueAmbienceTracks["GOBLIN"] = "GlueScreenDwarfGnome";
GlueAmbienceTracks["TAUREN"] = "GlueScreenTauren";
GlueAmbienceTracks["SCOURGE"] = "GlueScreenUndead";
GlueAmbienceTracks["NIGHTELF"] = "GlueScreenNightElf";
GlueAmbienceTracks["DRAENEI"] = "GlueScreenDraenei";
GlueAmbienceTracks["BLOODELF"] = "GlueScreenBloodElf";
GlueAmbienceTracks["DARKPORTAL"] = "GlueScreenIntro";
GlueAmbienceTracks["CHARACTERSELECT"] = "GlueScreenIntro";
Add your custom class to this table.