Is this a correct message?

[Göran Uddeborg]

While updating the Swedish translation of binutils I came across this
message:

    #: windmc.c:307
    msgid "try to add a ill language."

Is that really what it should say?  I'm guessing it is some kind of
misspelling, but I'm not sure what it should have been.  Maybe because
I'm not familiar with mc files.

If it indeed is the intended message, could you explain what it means?
Can a language be ill?  Did it catch a cold? :-)