clip export fail
 

we are trying to export an animation clip from our low res character, but every time we push the export button maya gave us this kind of message:

doExportClipArgList 1 {"clipEditorPanel1ClipEditor"};
// Error: File contains unknown nodes or data. To preserve this information, the current file type cannot be changed. //

what does this mean? we are just selecting the nodes with an animation curve.

thanx