This has nothing to do with code-signing.

In Line 76 you are trying to add a file (Install File action) and this file
does not exist or is locked. It's not the code-signing process that fails
here. Check your Line 76.

And to handle dual SHA-1/SHA-2 or SHA-2, follow the instruction from my
previous message.

http://www.lindersoft.com/forums/showthread.php?47199

Friedrich