Avast wrong report tcpz-x86d.sys as rootkit, Please remove it from virus list.
tcpz-x86d.sys is a part of my software TCP-Z.
TCP-Z is just a simple tool for monitor status of network, and adjust half open connection limited in runtime.
I take it from your image that you opted to Report as a false positive ?
The file will be uploaded to avast on the next update, Auto or Manual, so you can initiate a Manual iAVS update and that will upload the file right away, see image example.