What steps will reproduce the problem?
Take a color picker option that works perfectly fine without alpha.  Then change hasAlpha from false to true, and add defaultA and currentA to the array.

What is the expected output? What do you see instead?
Expected: there to be an alpha slider in the color picker, with the default/current values set
Instead: the color picker does not display in the options window, and an error is generated (below)

What version of the product are you using?
r41  (WoW-3.0-release-2)

Do you have an error log of what happened?
[2008/11/03 22:20:15-1204-x1]: LibSimpleOptions-1.0-90039 (PocketPlot):911: attempt to perform arithmetic on local 'currentA' (a nil value)
PocketPlot-2.0\pocketplot.lua:181 in function <Interface\AddOns\PocketPlot\pocketplot.lua:165
PocketPlot-2.0\pocketplot.lua:221 in function `controlCreationFunc'
LibSimpleOptions-1.0-90039 (PocketPlot):101: in function <...face\AddOns\PocketPlot\libs\LibSimpleOptions-1.0.lua:99
<in C code>: in function `Show'
Interface\FrameXML\UIOptionsFrame.lua:204 in function `InterfaceOptionsFrame_Show':
Interface\FrameXML\UIOptionsFrame.lua:484 in function `InterfaceOptionsFrame_OpenToCategory':
LibSimpleOptions-1.0-90039 (PocketPlot):946: in function `value'
Interface\FrameXML\ChatFrame.lua:3212 in function `ChatEdit_ParseText':
Interface\FrameXML\ChatFrame.lua:2911 in function `ChatEdit_SendText':
Interface\FrameXML\ChatFrame.lua:2932 in function `ChatEdit_OnEnterPressed':
<string>:"*:OnEnterPressed":1: in function <[string "*:OnEnterPressed"]:1>

Please provide any additional information below.