No, it happens sometimes - as long as the majority of your results are OK then there isn't a problem
An invalid result means:
The information that you sent back to the server did not validate against the other workunit results that have come back from other members. - you still recieve credit for this.
And for your info:
An inconclusive results means:
They have not been validated yet. They are labelled inconclusive because the minimum amount of results needed to be returned back for validation has not happened. This means that the quorum needed to validate a workunit has not been met. Usually this is caused by one or more results being invalid (ie one like yours! ) and not comparing to the other results.
What happens then, is they send out the unit to be crunched again, and it may take a bit longer for you to get the credit.
If you get an Error Result, you will not get any points.