I created an interactive dynamic form in Designer 7 and it works in the Designer Preview PDF view, but when I open the form using Acrobat Pro, the form is static - I cannot enter any data and none of the drop down boxes work. The form is saved as a dynamic PDF Form file and when I go the Forms menu in Acrobat 7 the "Make Form Fillable in Adobe Designer" selection is greyed out.
Sounds like you do not have the form "Enabled User Rights for Adobe Reader".
Open the form in Acrobat Professional. Select from the Advanced Menu option "Enable User Rights for Adobe Reader". Save form while in Acrobat Professional.