trouble shoting "Pin 'hm2_5i25.0.7i76.0.0.input-24' does not exist 4977"

I checked all of these things I am nearly sure all of these are correct. Any other ideas?

I am not sure exactly what you mean by this. There are multiple plugs?

Can you run

sudo mesaflash --device 5i25 --readhmid
and post the results here?

Also how are the 7I76 and 5I25 cable power jumpers set
and do you have 2 yellow LEDS illuminated on the 7I76?

Diagnostic = Bad Cable @ DB25 to IDC26

7i92 Manual has statement:
the 7I92 can supply up to 1A of 5V power to each of the daughter cards.  If you use this option you must verify that the interface cable does not tie the eight parallel port ground wires together as some cheap printer cables do. Mesa supplied IEEE-1284 cables are the best option

7i92 Manual has the DB25 to IDC26 Pinout: 
DB25
1 & 14
2 & 15
3 & 16
4 & 17

Is this the correct Pinout for Mesa DB25M to IDC26?

Yes, a IDC cable HDR26 --> DB25 has the correct pinout.
(with pin 1 --> pin 1 and HDR26 pin 26 unconnected)

.

.

A correctly made IDC cable is all that's required .
(as long as you have IDC-HDR26 pin1 to IDC-DB25 pin one, its correct)

Is field power connected on the 7I76?

Normally you would _not_ connect to VIN but rather connect
to field power (and leave W1 in the left hand position)

7i92_7i76x1D.bit

DB25
1 & 14
2 & 15
3 & 16
4 & 17, etc....

This Pinout tested Success for:
Yes 5V Cable Power 7i92 to 7i76

Yes Both Power LED are ON.
CR1 5V Cable Power from 7i92
CR2 24V Field to VIN

Tested Fail for:
Same problem Motors won't turn, Limit Switches fail to compile...
hm2_7i92.0.7i76.0.0.input-oo "does not exist"

Fail yet unknown
although CR1 & CR2 ON & yes 7i92 5V Cable Power @ 7i76D.

Again, a correctly made IDC cable is all that's required .
(as long as you have IDC-HDR26 pin1 to IDC-DB25 pin 1, its correct)

A hand soldered cable can certainly be wrong however.

For the 7I76 to work with the 7I92, you need:

1. 7I92 with 7I76 firmware installed (verify with mesaflash --readhmid option)
2. 7I76 connected to primary 7I92 connector (P2) with proper (pin 1 to pin 1, IDC) cable
3. 7I76 has both 5V and field power supplied (and W1 left)
4 7I76 W3 left (operate mode)