Trying to determine how a form renders its components vs executing statements

[Cloud]

I was given an asp.net project to work on which was working fine but I believe they changed servers and maybe put on a newer version of IIS as well and then it stopped working. I fixed it but now they wanna know why it gave the problem in the first place.

It's an edit page form in which a dropdownlist is populated by a database and set to a value that was previously selected when the data was originally added. A method uses the value displayed in the combo but although it's displayed, that value isn't returned. My fix was to take the value from the database unless the page is a postback then it gets it directly from the dropdownlist. I'm assuming that means the c# statement gets executed before the combo is populated or at least before the selection for the dropdownlist is set. What i'd like to know is whether different server and/ or different iis would make the page render differently or the code get exeucted at a different time as the page was working fine before it got moved.

[Cloud]

Ok, so now i'm hearing it didn't stop working because of IIS difference. It was working and the servers got moved from here in Jamaica to the US and that's when it stopped working so we put the code on a local server and that's where I worked on it and made the changes. Any ideas?