By looking at the screen shot you can see the error for line 21...I fixed that with the code below. Also you can see the sword with Runes.
Code:
-- Button to lock/unlock runehero
local lockButton = CreateFrame( "CheckButton", "lockButton", rhOptions, "SettingsCheckBoxControlTemplate");
lockButton.text = _G["lockButton".."Text"];
lockButton:SetText("Lock RuneHero");
lockButton:SetPoint("BOTTOMLEFT", titleString, 0, -40);
lockButton:SetScript("OnClick", RuneHero_Lock );
lockButton:SetChecked(true);
But upon applying this fix is does eliminate the errors and allows for the settings to show up in the Options Tab, but the Sword disappears.
https://imgur.com/a/uNmdEON
Is there something I'm overlooking?