The error explains the problem.
TabPages are what you need to add to your TabControl, not buttons. The TabPage will give you all of the functionality needed to flip back and forth between your various IMs.
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Read this if you want to know how to get a correct reply for your question:
http://www.catb.org/~esr/faqs/smart-questions.html
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.: Wrox Technical Editor / Author :.
Wrox Books 24 x 7
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