"Equation does not have estimates"

[JASON]

Hi, I am using Version 8. My question has to do with the fact I got the following statement from EViews work file, as shown below. Any tips to fix the problem? Please adise.
Kind regards,
Jason
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Equation does not have estimates

Estimation Command:
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LS LOG(RATEOPPRV_AUT) C LOG(RPCETOTTO_AUT) LOG(YPCOM_AUT) @TREND

Estimation Equation:
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LOG(RATEOPPRV_AUT) = C(1) + C(2)*LOG(RPCETOTTO_AUT) + C(3)*LOG(YPCOM_AUT) + C(4)*@TREND

[EViews Gareth]

What happens if you hit the estimate button?

[JASON]

I would get "insufficient number of observations" error message. When I check the history data file, (this indicator being a ratio of two indicators) there are no missing values. However, in the work file, the derived ratio only contains one observation.

[EViews Gareth]

With only one observation, the equation cannot estimate (hence the error message).