Mask and email form- where is the problem?

I have to correct someones work, and unfortunately even If I have foun an error, I am not able tu nderstand it and solve it
As structure of the site, we have base.swf- the main page and some others sub_sites like contatti.swf
In contatti.swf does not work email form- when I am tryng to reach it via bas.swf and button.
Apart it works perfectly, so I went to base.fla to see where is the problem and I saw that there is a big mask (called “quadro”) on the main scene and it simply disturbs to use email form.
Why is it so? That mask in other swf disturb to work email form?
How to solve it?
I am hopeless…
Here is the link to file-source, could someone look at this please?…ecef/sito.html