could you share the system log from the weewx start until the first archiving and report generation !?
also share the [[FTP]] stanza from your [StdReport] section in weewx.conf (remove, scramble username and password !).
Best is the whole weewx.conf (without passwords

) so we can see which skin you are using...
Then we have a better possibility to see what might have gone wrong.
When you connect to your Linux computer via VNC, you can mark and copy the syslog text and then paste it into a Windows document or in the browser.
If your Linux installation doesn't have a UI and only a CLI, mount one of your Windows drives in the same network to your Linux server:
sudo mkdir /mnt/transfer #create a mount point
sudo mount -t cifs -o username=Win-USERNAME,password=Win-PASSWORD //your-Win-PC-IP-Address/c /mnt/transfer
then you can copy the syslog to your PC - and edit it there
sudo cp /var/log/syslog /mnt/transfer
this will copy the syslog to the root directory of your Win-PC C: drive