the PI ActiveView control needs to be loaded, and the connection to the PI Server needs to be opened as well. This might take time when you start your application the first time and when you are accessing the PI server from PI SDK as well. You may check with the AboutPI-SDK how long it takes for an initial connection. Connection problems/delays can be troubleshooted by TechSupport (firstname.lastname@example.org) - there are various reasons for that (network latency, reverse name lookup, etc.).
The existence of the acview.exe process is is intended behavior, PI-ActiveView has a process (acview.exe) that continues to run for 5 minutes after the last instance of the PI-ActiveView control is closed.