[錯誤訊息]Timeout expired. The timeout period elapsed prior to obtaining a connection from the pool.

[錯誤訊息]

Timeout expired.

The timeout period elapsed prior to obtaining a connection from the pool.

This may have occurred because all pooled connects were in use and max pool size was reached.

這是一個DB Connection Pool的問題，

一般來說我們會用conn.close()來關閉連線而已。

嚴格來說，還要將資源釋放才可以 conn.Dispose()

相關參考網址：http://blogs.msdn.com/angelsb/archive/2004/08/25/220333.aspx