Hi yall, recently I'm finishing this font at Fontlab 5, I decide to add OpenType Features such as stylistic alternates and some ligatures, then when I start doing the kerning stuff, I add some kerning classes, since this, I started to have this problem when I want to test (compile) the OT features, this is what I get:

[FATAL] aborting because of errors:
syntax error at ","
[/Users/Rodrigo/Library/Application Support/FontLab/Studio 5/Features/fontlab.fea 1]
Anyone know how can i solve this problem? I notice that when I erase all the kerning classes, OTF works normally, but when I add just one KC, this error appears, don't know why either how to solve it.
Thanks for your help!