Urgent help - 1.5.61 pro no field titles appearing

We have not had such problem yet, it seems to be a language file problem because some strings are displaying correctly, some (most of them) not.

The language files react oddly when being typed in a wrong format. It must be UTF-8. If you edit the file with a windows editor, it could be the reason.

Other reason could be some unescaped characters. For example the quote characters \" and \' should always be escaped just like \\\" and \\\'

Sometimes this leads to an unwanted display (as KISS Advertiser displays i.e. \"Owner\\\'s Address\") but the file will be safe.

Ummm.... Honestly speaking I do not really know what the problem could be.
Are all field labels gone? Or only those on the first tab.
If all field labels are lost, you might have damaged or deleted the language file, in this case just copy the language file en-GB.com_ksadvertiser.ini to the language directory.

But I do not believe that this is the problem as KISS Advertiser should at least display the label ressources which are part of the controller file - rather than displaying nothing. It\'s odd that \'category\' is being displayed and all other ressources are gone.