invalid input msg for perl reg exp not translating

Hi,
I have searched the forums and checked and rechecked my work.
It seems that the error in case of invalid input for a custom perl regular expression is not translatable.

I have set the error in case of invalid input to be _UE_LUNAR_BIRTHDAY_MSG

and have placed
DEFINE('_UE_LUNAR_BIRTHDAY_MSG','my translated error message');

in my language file.

The translations for my field names, information etc are displayed succesfully, but the tranlsation for the error message is not.

Does anybody know if there is somewhere in the php code that I can hardcode a single error message for all perl regular expressions (I will hard code it already translated) ? My website only has one language...its just not english (or english characters). Alternatively, I can set it to one of the default Joomla error messages (which are translated) like 'error' or something, if someone can tell me how ?? I dont need to provide details of the error, just an elegent way to say that the field in question has a mistake.

Thanks in advance for any help.