I don't know if the 23-characters long tag limitation has been removed in later releases, but, unfortunately, Android 1.1 has it. I think the tag length should be checked and the tag eventually trimmed in order to avoid incurring in this exception without having to change the application logging code.
The check is performed into the native method android.util.Log.isLoggable()
To reproduce the problem in Android 1.1:

String ALLOWED_TAG = "abcdefghijklmnopqrstuvw";
String TOO_LONG_TAG = "abcdefghijklmnopqrstuvwxyz";
Log.i(ALLOWED_TAG, "blabla");
Log.i(TOO_LONG_TAG, "blabla");