網上搜來的：
Reason:
This is probably because there is no OLE editor registered against the type of file you were trying to open.
Class ID not found in registry result = -2147221018
Delete C:\Documents and Settings\Administrator\workspace the whole folder,then restart Eclipse
It is ok.
原來是eclipse 打開了excel 沒有關，再打開eclipse 的時候就會報這樣的錯。