The original ROM...
Is it for a MDPI device?
If it's for Mytouch 4g...the Mytouch 4g is HDPI
If the original ROM only had HDPI framework files, than the ROM will look very messed up...
We'll see....I guess
Oh yeah I forgot
It's not signed.
Use Clockworkmod Recovery and it won't check for signatures
Heres cwm4 by roalex: http://dev-host.org/nWo
It's beta but works perfect for me
Do all the wipe options in mounts