Based on your die statements, I don't think that the issue is with the $ftp->put line. The error message that you mentioned ("Cannot open Local file sudolog_2010Jul_Infodevl: A file or directory in the path does not exist") looks like the die statement from where you tried opening the file.

I agree with Corion about the problem being that you're in the wrong directory. Unless your Perl script is run in the same directory as the 'lsfiles' file that you're trying to create, the open command will look in the path that the Perl script was invoked from and will fail to find it.