i dont know of a limit of lines ..... altho it may have a limit of file size .. i think someone had said the mirc editor only reads up to 200 kb but um i dont know for sure if there is a limit ... again could be wrong
i found it out myself had some problems with strings longer than 950 try to write a 1000 chars long line in remote edit window close and reopen that window and look how long the line is