Maya produces errors like this (it may also read "Cannot convert data of type string to type string," and these errors cause Smedge to abort the work because it thinks that there is some kind of actual error that affects rendering.
Actually, what Maya is complaining about is that you have multiple nodes with the same name (probably under different group nodes). These nodes can cause issues with some of the scripts that Maya uses. Often, these errors are benign, meaning that the renderer is somehow able to work around it anyway, but because Maya is using the "Error" notation, there is no way that Smedge can know this.
There are several workarounds. First, you can either disable error text detection in Smedge, or at least add an error ignore string to ignore, say, "convert data of type" to ignore any error message that contains this text.
But, in general, it's better to fix the problem in your scene so that Maya does not output the error message at all. Often, these kinds of errors can be fixed in your scene simply by renaming the objects so that they do not have conflicting names. If you duplicated a hierarchy, use the "Assign unique name to child nodes" option box in the Duplicate Special command to ensure that these sorts of naming issues don't crop up in the first place.