According to an FAQ on Adobe.com,

During the month of June 2008, certain product trials that are launched for the first time (regardless of when they were installed) will function for only one day instead of 30 days, due to an error in a line of code that counts down the remaining days in a trial. You will not experience this issue if you have launched your trial before June 1, 2008, or do not launch it until July 1 or thereafter.

Therefore product trials are unavailable for download from Adobe.com at the moment.  Customer Service says, "If you tried to use an Adobe trial in June and it expired after one day, please visit www.adobe.com/go/trialupdate for more information."