I checked the files and it looks that you applied only 2 changes (or at leat my tool that I use to check files differences is telling me so)
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<add name="ASPxHttpHandlerModule" type="DevExpress.Web.ASPxClasses.ASPxHttpHandlerModule, DevExpress.Web.v9.3, Version=9.3.3.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" />
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<pages enableSessionState="true" enableViewState="true" enableViewStateMac="true" validateRequest="false" pageParserFilterType="Microsoft.SharePoint.ApplicationRuntime.SPPageParserFilter, Microsoft.SharePoint, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" asyncTimeout="7">
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You need to add the missing changes: safe control, the session and the handlers.
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PS
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We just released a newer verison of dicussion webpart, please check the link below
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