In case anyone else gtets into a mess with this …

Th name of an imported mesh in SL is taken from the “name” attribute of the <geometry> tag defining the mesh. Im Blender 2.49b, the exporter took this attribute from the Blender object name. Unfortunately, in Blender 2.63 it is taken instead from the data block. This means that renaming your objects so that they have reasonable names sfter import is no longer effective. Instead you have to rename the data blocks. You can do that in Outline view or in the property editor for object data (the inverted triangle of vertices).

If you use the same datablock for multiple objects, the exporter uses instancing, with the geometry appearing only once in the collada file, referenced in multiple nodes of the scene, each with their own transformations. Unfortunately, the uploader does not use instancing (although it does reads it properly from the collada). Instead, it ulpoads separate meshes. Since only one of these can use the dtablock name, the others appear to be renamed to “Object”.

Gaia Clary points out in a follow up post that the problem is being fixed in Blender 2.64. See her post.

This issue has been “fixed” by adding a new select option.In fact i believe that the SL Importer takes the Object name from the wrong place. It should use the information provided in the visual scene description. But well…

The new option will be available in Blender 2.64.