11/14/2011 2:04:19 AM
Are there any exceptions logged in Site Manager -> Administration -> Event log or, in the system's Event viewer?
From your description it seems that your application is being recycled after some idle time (what are the IIS settings?). Then, the first start can take a longer time since the application is starting and everything is being loaded to cache and memory.
If there is set any idle time - you can remove this setting or set the IIS to ping the site every few minutes to keep it alive.