The HyperDerp loader code is broken due to an update in HP's gameversion and wasn't perfect in the first place.
It could very easily be fixed in <5 minutes but Darakath is inactive now so I don't know. Any other person with the smallest amount of AS3 knowledge could make one too, but for most it isn't worth their time.
Honestly guys, it's a private server - just play it normally
@JamesRo mark as patched?