网上搜来的：
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.
原来是eclipse 打开了excel 没有关，再打开eclipse 的时候就会报这样的错。