Yeah, most likely- that .jar you whipped up works fine for me, so thanks for that. What's the procedure? Make a jar out of everything except lwjgl.jar+natives first? Glad it works smoothly outside the Mac, anyways.
Not difficult to create a executable jar for the above project.
1) Add all your project jars - since you only use lwjgl.jar and your own classes that all you need to add there. Your src folder wasn't in a jar/zip so just put it in one and added it to the list.
2) Add all the natives your project uses - added all the LWJGL *.dll (windows), *.so (linux) and *.dylib,*.jnilib (mac) natives files to the natives tab.
3) Add the main class: src.main.Loop
Thats it, click create jar.