In order to add a new web part to Sharepoint 2007 (MOSS) you need to add the assembly information to the <SafeControl> list inside the sites Web.Config file. When doing so make sure to type carefully. If you make a mistake when editing the config file, the page will not render correctly. If the page is NOT rendering correctly for you, check the Application Event log for details, this may point you in the right direction.
Pay special attention to the casing for the attributes. They ARE case sensitive.
Invalid (namespace is not cased correctly):
<SafeControl Assembly="xxxx, Version=1.0.0.0, Culture=neutral" namespace="xxx" TypeName="*" Safe="True" AllowRemoteDesigner="True" />
Valid (namespace is not cased correctly):
<SafeControl Assembly="xxxx, Version=1.0.0.0, Culture=neutral" Namespace="xxx" TypeName="*" Safe="True" AllowRemoteDesigner="True" />
Just thought I would say my findings/pain with everyone.
Till next time,
