The error message corresponds with the Windows error code TYPE_E_LIBNOTREGISTERED (0x8002801D). Apparently that can occur when loading a COM type library (which can be triggered by several API calls) that isn't properly registered [1].
Just speculating, but since the problem only occurred once, perhaps there was a temporary problem (i.e., reading the hard drive, accessing memory, etc.) which resulted in this error.
[1]
http://search.microsoft.com/results....ERED&mkt=en-US