SharePoint Designer, asp.NET

I have created a dataview to an SQL database and added the edit function.

This is the default tag when I add the edit

I have changed the text box to a drop down box and this is what I now have

For some reason when doing this one change if data is edited it no longer saves but goes back to original, even if another column is a text box as long as this drop down box is in the edit function for the database I am unable to edit and save any data.

Any help would be greatly appreciated

Thanks :)