Hi there!
To introduce myself - I am a total newbie at XNA and 3D programming. I modeled a little house in Blender (version 2.48).
I exported that model to fbx format and tried to add it to the content pipeline of my game project.
When ever I try to compile/run my project - I end up with the following error message in visual studio 2008:

Fehler    3    Building content threw InvalidOperationException: Position index out of range. VertexContent.PositionIndices contains a value outside of the range of the parent MeshContent.Positions collection.
   bei Microsoft.Xna.Framework.Content.Pipeline.Graphics.IndirectPositionCollection.get_Item(Int32 index)
   bei Microsoft.Xna.Framework.Content.Pipeline.Graphics.IndirectPositionCollection.<GetEnumerator>d__0.MoveNext()
   bei Microsoft.Xna.Framework.Content.Pipeline.Graphics.IndirectPositionCollection.CopyTo(Vector3[] array, Int32 arrayIndex)
   bei Microsoft.Xna.Framework.Content.Pipeline.Processors.VertexBufferContent.Write[T](Int32 offset, Int32 stride, IEnumerable`1 data, TargetPlatform targetPlatform)
   bei Microsoft.Xna.Framework.Content.Pipeline.Graphics.VertexContent.CreateVertexBuffer(VertexBufferContent& vertexBuffer, VertexElement[]& vertexElements, TargetPlatform targetPlatform)
   bei Microsoft.Xna.Framework.Content.Pipeline.Processors.ModelProcessor.ProcessMesh(MeshBonePair meshBonePair, ContentProcessorContext context)
   bei Microsoft.Xna.Framework.Content.Pipeline.Processors.ModelProcessor.Process(NodeContent input, ContentProcessorContext context)
   bei Microsoft.Xna.Framework.Content.Pipeline.ContentProcessor`2.Microsoft.Xna.Framework.Content.Pipeline.IContentProcessor.Process(Object input, ContentProcessorContext context)
   bei Microsoft.Xna.Framework.Content.Pipeline.BuildCoordinator.BuildAssetWorker(BuildItem item)
   bei Microsoft.Xna.Framework.Content.Pipeline.BuildCoordinator.BuildAsset(BuildItem item)
   bei Microsoft.Xna.Framework.Content.Pipeline.BuildCoordinator.RunTheBuild()
   bei Microsoft.Xna.Framework.Content.Pipeline.Tasks.BuildContent.RemoteProxy.RunTheBuild(BuildCoordinatorSettings settings, TimestampCache timestampCache, ITaskItem[] sourceAssets, String[]& outputContent, String[]& rebuiltContent, String[]& intermediates, Dictionary`2& dependencyTimestamps, KeyValuePair`2[]& warnings)    C:\Dokumente und Einstellungen\Chriss\Desktop\WinFormsGraphicsDeviceSample\WinFormsGraphicsDevice\Content\models\haustest.fbx    Content

I have no idea where that error message comes from - because other model (less complex) just work fine. Could it be a bug in the importer?

Any tips would be very welcome - because I'm already at the end of my very limited knowledge about Blender and fbx :-/

Sometimes I get that too, usually when I've been moving lots of vertexs around, or deleting others. I haven't been able to solve it, other than by rolling back to an earlier version of whatever model I was working on (when it imports fine) and try to do it over again. If there's a way to fix this I'm very interested in it!

The FBX importer in XNA 3 has been "played with" for wont of a better phrase, and a lot of issues like this are coming up.

One thing you can try is to get a copy of the FBX sdk, it's free, and use the conversion app that comes with it.

blender typically outputs fbx 2006, if you convert it to fbx 2009 this error will often disapear.

Awesome, I'll look that up!

Hey there!
Thank you for the tip with the converter! :) Unfortunately it did not work for me :(
Guess I'll have to recreate my model...

Thank you anyway.

Well it was worth a try, getting an animated mesh into XNA is a none trivial task.

Good luck.

[wrong thread] >_<

[bumping an old thread for the sake of a possible answer]

My model got this error when I started using vertex colors on it but didn't apply vertex colors to every vertex. It stopped giving that error when I made sure all the vertices had a color assigned.

I ran into this problem as well.  It turns out to be pretty simple.  Blender is including edges that don't make up triangles in the exported FBX.  When the XNA importer runs into an edge (two vertex indices instead of three) it bombs.  The solution is to open the blender FBX export script (export_fbx__for_xna.py), search for

Matt Hopkins:

The solution is to open the blender FBX export script (export_fbx__for_xna.py), search for

for ed in me.edges:

and comment out from that line up until 

"del LOOSE"

Now the orphaned edges won't be included in the export and XNA will be able to process the FBX.

This fixed the problem (for me, at least). Thanks.