If there is a code error, it would be helpful to post the contents of the "Problems" pane. If you're in code view, the problems panel is on the bottom, near where the Timelines panel is in design view.
1180: call to a possibly undifined method contact_us_button_clickHandler main.mxml project src flex problem
1180: call to a possibly undifined method gallery_button_clickHandler main.mxml project src flex problem
1180: call to a possibly undifined method services_button_clickHandler main.mxml project src flex problem
The problem is that your interactions are in a bad state. If you can open your project, you may be able to remove the interactions from the contact_us, gallery, and services buttons. If not, you will need to bring your project into Builder and remove the lines
Alternatively, if you post your project, someone on the forums may be nice enough to fix it up for you.