Android Question Seekbar values in array unexpected

Hello,

I have a seekbar which according to it's properties should go from 0 to 255.
label2.Text shows the correct value (0 to 255)
However the array contains 0 to 127 correctly (halfway up the seekbar) then the seekbar.value puts -127 to -1 for the rest of it's travel.

Sub SeekBarred_ValueChanged (Value As Int, UserChanged As Boolean)
label2.Text="Red Value - "& seekbarred.Value
pmxpacket(pmxpacketentry)=seekbarred.Value

What have I done wrong ?
Thanks in advance