Instrument variable definition

[alps]

Hello,
I am trying to run a 2SLS regression which has 11 monthly dummies and one instrument lrefpd. Depending on the place of @lrefpd I am getting the following error:

equation s1.tsls(n) lgasc_cap c lrgaspr lr_inc @ lrefpd @expand(@month, @drop(12)) (error message: order condition violated insufficient instruments)

equation s1.tsls(n) lgasc_cap c lrgaspr lr_inc @expand(@month, @drop(12)) @ lrefpd (takes lrefpd and the monthly dummies as instruments, but only lrefpd is an instrument)

Should I just create and put the dummy variables in the equation?

I have Eviews 6.

Thanks
Alps

[EViews Gareth]

I don't understand the question.

[alps]

sorry for not being clear.
I have this 2SLS regression, the instrument variable is lrefpd. But when I try to run the equation below I receive an error message.

equation s1.tsls(n) lgasc_cap c lrgaspr lr_inc @ lrefpd @expand(@month, @drop(12)) (error message: order condition violated insufficient instruments)

Then I change the location of @lrefpd in the equation and put it in the end and run it

equation s1.tsls(n) lgasc_cap c lrgaspr lr_inc @expand(@month, @drop(12)) @ lrefpd

Then when I look at the result I realize that in addition to lrefpd, all the other 11 seasonal dummies are taken as instruments as well.

My question, how can I define the instrument variable lrefpd and run a simple 2SLS regression.

Thanks very much for your help.
Alps

[EViews Gareth]

You need more instruments.

[alps]

I see. So it isn't that where I place the instrument variable in the equation; I just need to define more instruments. I thought Eviews was confused when there were more than one @ signs.
Thanks a lot for your prompt response.