I know little about Linux, but here are my suggestions. Please let me know if this does not work.
1. Go to the Twonky browser settings page and write down your license key if you haven't already.
2. Do here and download the Linux version: http://www.twonky.com/support/downloads.aspx
Note: This is not the version for NAS users. If you need that let me know and I'll post the link.
3. Uninstall the old version(s) of TwonkyServer 4.0, 5.0 or 6.0.
4. Install the full version of TwonkyServer 7.0.
5. Enter your license key when asked.