For those brave souls with an editor, here's the fix to get you by until we get a new official build:

edit /usr/lib/mlbviewer_gui/MLBviewer/mlbtv.py

go to line 414

add ", re.I" as a new argument to the function call.

Here's what the line looks like when done:

pattern = re.compile(r'Welcome to your personal mlb.com account.', re.I)

It's Python, so don't mess up the leading indentation.

Save and close mlbtv.py

Start MLBViewer and you should be good to go. I am.