So, is there really no one who can help me?

[spaceman]

Simple setup:

A K5000S connected to the MIDI input of an EMU 1212M
When I try to select E-DSP MIDI Port [BC00] as remote controller (the midi interface)

I get

"Failed to open MIDI Device "E-DSP MIDI Port [BC00]"

I can't use my keyboard in Live, it works perfectly in any other host (Sonar 4, FL 5, Reason, EnergyXt and Renoise)

It worked once in Live which makes me believe Live has written a config file or registry value that's causing problems

Don't tell me this is not Live related

[spaceman]

I installed Maple virtual MIDI cable and even WITHOUT using it in Live 4.. all of a suddon I CAN select my cards MIDI interface again

[Ulf]

Try to delete this file "MIDICheck.cfg"

You can find it here:
Windows:
Documents and settings/user name/applicaion data/ableton/live 4/preferences/preferences.cfg.
-> Make sure that the folder is not hidden for display by Windows!

Mac OS X:
/Users/your_name/Library/Preferences/Ableton/Live 4.xy/