Millisecond Forums

Hi all! When I present a surveypage containing 2 textboxes I need participants to be only allowed to introduce values that sum 5 in total (not higher nor lower, e.g. 2 and 3), if they introduce values different than 5 I would like them to see a text indicating the error so they can correct it. I have tried as follows:

<surveypage CoalitionOffer>
/ questions = [1=OfferBox1, OfferBox2]
/ stimulusframes = [1 = OfferPic, CoalitionOfferText, OfferBoxYou, OfferBoxPartner]
/ showbackbutton = false
/ showquestionnumbers = false
/ showpagenumbers = false
/ showmousecursor = true
/ finishlabel = "Click here to continue"
/ branch = [if (textbox.OfferBox1.response + textbox.OfferBox2.response != 5) text.erroroffer]
/ branch = [if (textbox.OfferBox1.response + textbox.OfferBox2.response == 5) likert.Liking1]
</surveypage>

<text erroroffer>
/ items = ("please introduce the correct values")
/ color = (0, 255, 0)
/ fontstyle = ("Arial", 3%, true)
/ position = (50%,50%)
/ vjustify = center
</text>

In this case, If they introduce “5 and 6” they are not allowed to continue but the error message is not displayed. And f they type “5 and 4” they move to the next page "likert.liking1".

Thank you in advance for your help!!
Anabela