Thank you for the suggestions.
jay - I am not entirely sure, but whether I specify readonly in the tag, or change it programmatically via ASP.Net, I get the same result. The field appears to become unprotected, but when I submit the form the data does not come across. I am not sure why, and I am not sure if I will ever truely find an answer. But I did find something that did finally work. I am now setting the readonly property via javascript only. In my $(document).ready function I check if the checkbox is checked and if so I protect the fields and if not I don't. Also, if the checkbox is checked/unchecked I run function that sets the readonly accordingly. Since all manipulation of the readonly attribute/property is done via js/jquery it seems to be working now. However, I am still having an issue with the input mask for the phone number.
charlietfl - I have tried uploading .bmp, .jpg and .tiff, all without any success. I have a feeling it may be because of my firewall here at work, or that the function within the website is not working or liking my files.
Again, thanks for the responses. If you have any ideas why changing the readonly property would affect my input masks, please let me know.