I have reported this bug previously.
I have now made tiny progress in localizing the bug.
The error occurs in the condition-case in ecb that ends like this:
"Errors during the layout setup of ECB."
This is around line 1805-1852.
The error reported is "Wrong type argument: stringp, nil"
which matches this error in *messages*:
tramp-tramp-file-p: Wrong type argument: stringp, nil
When I get this error, ecb-activate fails, and ecb-deactivate doesnt
If I comment out the condition-case, ECB starts, that is, displays its
layout. all windows look ok, except the file window, which seems
consistent with the tramp error.