When you add a web part, if you get an error saying "The type is not registered as safe," even though you do have a valid SafeControl entry for your web parts, then try adding the assembly's strong name to each .webpart file.
Here's an example. The assembly is ArrowWebParts.dll. It's strong name is "ArrowWebParts, Version=3.0.0.1, Culture=neutral, PublicKeyToken=bface3e8a4e95820". Originally, in the type element, I just had "ArrowWebParts.DataDefinitionWebPart", and I was getting the error. After adding the strong name, the error goes away!
<webParts>
<webPart
xmlns="http://schemas.microsoft.com/WebPart/v3">
<metaData>
<type
name="ArrowWebParts.DataDefinitionWebPart, ArrowWebParts, Version=3.0.0.1, Culture=neutral, PublicKeyToken=bface3e8a4e95820" />
<importErrorMessage>Cannot import ArrowWebParts.DataDefinitionWebPart.</importErrorMessage>
</metaData>
<data>
<properties>
<property
name="AllowZoneChange"
type="bool">True</property>
<property
name="ExportMode"
type="exportmode">All</property>
<property
name="HelpUrl"
type="string" />
<property
name="Hidden"
type="bool">False</property>
<property
name="TitleUrl"
type="string" />
<property
name="Description"
type="string">Wizard for creating a Windward data profile.</property>
<property
name="AllowHide"
type="bool">True</property>
<property
name="AllowMinimize"
type="bool">True</property>
<property
name="Title"
type="string">Create Windward Data Profile</property>
<property
name="ChromeType"
type="chrometype">Default</property>
<property
name="AllowConnect"
type="bool">True</property>
<property
name="Width"
type="unit" />
<property
name="Height"
type="unit" />
<property
name="HelpMode"
type="helpmode">Navigate</property>
<property
name="CatalogIconImageUrl"
type="string" />
<property
name="AllowEdit"
type="bool">True</property>
<property
name="TitleIconImageUrl"
type="string" />
<property
name="Direction"
type="direction">NotSet</property>
<property
name="AllowClose"
type="bool">True</property>
<property
name="ChromeState"
type="chromestate">Normal</property>
</properties>
</data>
</webPart>
</webParts>