Edit Definition ? Hate to ask but.....

I feel stupid for asking because Ive used SW for along timeand have seen this message before but after doing so research onthe Internet and my SW Bible I have yet to get the answer Imlooking for. I opened an assembly that has an assembly in it and Ihad errors that told me to edit definition in the assembly that isreferenced in this assembly. I opened that assembly and there areno errors. I checked all the parts and there are no error's. Socould some please define exactly what I need to look for when i seethis error. ThanksSolidworksAssemblies