Gateway and netmask typically wouldn't be an issue if both are on the same LAN segment. Although it's technically possible to use something like 255.255.255.255, I wouldn't expect this normally.
To start, it would be best to list out here the full IP, subnet mask and gateway that the Owon and the PC have right now.
Then, what do you get when you ping the Owon from the PC?
Side note, is there a chance the PC is using wireless instead of the LAN? That could add some additional things in the mix to check out, such as wireless client isolation and WLAN-->LAN blocking.