It's funny, it appears to be an actual RPG Maker 2003 error and not my mistake -- all the RTP files are inside the game folder, and it DID run on my laptop with no RTP installed; while a friend who DOES have the rtp installed got the same error.
I contacted the staff to talk about it, because nowhere in the rm2k3 helpfile it states having to do anything other than adding the rtp files to the game project : /
anyway, i'm gonna make an installer version with bugfixes and a bit of expanded content and post it on RMN in a short while. :/
Thanks for the feedback!