InfoPath Dev

I have a Infopath Form out to the masses (let's say 75 users). All of them are not using it at the exact same time but in the form I have drop-down boxes from an Access DB.  At times some users select the drop-down in the form and nothing populates (while others use it just fine with no issues). This is not a server rights issue because ...

I have a form that will be standalone on a desktop that will be filled out and sent via email to the database and appropriate email recipients.  Is there a way for the email recipient of this form to then update it and resubmit while the data hits the database again (thus updating the record)? This is a Microsoft Access DB.

In my form I have a drop down box that selects a name of a building. When generating the email address I want it to use to submit the form I want it based on the building selected in the drop-down box. I have a listing of the emails in relation to the branch built in the access database the data is stored in.  So Question:  Form ...