That file is created by 'tar' when the KisMAC installer (or anything else that uses 'tar') unpacks a file from the archive whose full name is too long. The file itself contains the name which was too long.

You can avoid the problem by using 'gnutar' in place of 'tar'. Edit the installer script at /Volumes/KisMAC/KisMACInstaller.app/Contents/Resources/install.sh. Look for the line that starts with /usr/bin/tar, and replace that part with /usr/bin/gnutar. Save changes, run the installer, and voila, no more @LongLink file.