RE: Activity Fails with error 417. Reinstall fails with Returned Status 417 Daniel W Heichel 19.Jul.13 01:30 AM a Web browser LEI LEI - 7.0Windows
The first thing I'd recommend trying is to remove pid.nbf and restart Domino.
Most of the time, that will eliminate this error. However, if problems continue, post the entire message, this is likely only part of the failure message. Also, let us know if Domino fails to function, or if it's just LEI.
Additionally, as Barry mentioned in his response, an upgrade to at least version 8 of LEI and Domino would be a good idea at this point, because 7.0.4 is no longer supported.