Poedit Error: msgstr[0]' is not a valid C format string

[urgood2]

11:26:31: C:\Documents and Settings\Joshua\Desktop\Joshua\ko\Copy (13) of ko.po:12832: 'msgstr[0]' is not a valid C format string, unlike 'msgid'. Reason: The character that terminates the directive number 2 is not a valid conversion specifier.
11:26:31: C:\Documents and Settings\Joshua\Desktop\Joshua\ko\Copy (13) of ko.po:12838: 'msgstr[0]' is not a valid C format string, unlike 'msgid'. Reason: The character that terminates the directive number 2 is not a valid conversion specifier.
11:26:31: msgfmt: found 2 fatal errors

What does this mean? I get this error when trying to save my .po file in Poedit.

I noticed that translating messages with singular and plural forms was different. I don't know how to use this, I assume other people have gone through this also...

[urgood2]

Problem solved.The reason I could not translate for the plural form of the message was because Korean does not need two forms(plural and singular form).

[Buginator]

Problem solved.The reason I could not translate for the plural form of the message was because Korean does not need two forms(plural and singular form).

Does that mean you entered more data than it was looking for, and it gave you those error messages ?

[urgood2]

Actually, though, I really have no idea what caused the messages... I couldn't enter more data than usual, there was only one textbox.

EDIT I have found the problem. It was a mistake on my part. I accidentally changed the tokens in the translated strings. Like this:
"%s forms an alliance with %s" ---> "%u가 %s와 동맹을 맺었습니다"

Can you see the error?