Galaxy s4 Odin problem..at wits end!

[AC Question]

Ok, Galaxy S4 Gt i9505 (Australia).
Wanted to factory reset. Used Kies. Kies decided it needed a firmware update. Crashed during upgrade. Kies no longer could see phone.

Researched
(for mac) Found original firmware and got Odin and Heimdall.
Removed Kies.
Followed tutorials but kept getting file errors.

Tried with P.C. Downloaded Samsung drivers and Odin (v3.07 which was recommended).

Added firmware in PDA box.
(I9505XXUEMK9_I9505OPSEMJ5_I9505XXUEMK9_HOME.tar.md5)

Starts then returns a " Complete Write operation fail" message.

Tried a variant of the firmware. Same problem.

Any ideas?...Please!
Matt