So I have just read through this thread and puzzles me why you are trying to send the register name?? this will always stay the same if using the register plugin, you cannot change it.
In my own screen I use
function GetRegister(regname)
local hreg = mc.mcRegGetHandle(inst, string.format("Custom_Gui/%s", regname))
return mc.mcRegGetValueString(hreg)
end
function WriteRegister(regname, regvalue)
local hreg = mc.mcRegGetHandle(inst, string.format("Custom_Gui/%s", regname))
mc.mcRegSetValueString(hreg, tostring(regvalue))
end
so just change string.format("Custom_Gui/%s" to the reg you are using string.format("iRegs0/%s" and all should work fine
DazTheGas