No. The side switch can be set to controll either Muting or Screen Rotation. This is the expected behavior.
You can go to Settings->General->Use Side Switch to: to change it.
If its set to Lock Roatation, then Mute is controlled by double tapping the Home button to bring up the task bar and swiping to the left. The button all the way to the left will control the Mute option.
If the switch is set to Mute then Rotation will be in the taskbar instead.
Since there's only one switch it can only do one thing, and the other moves to the Taskbar.
The switch on the side of the iPad controls either rotation lock or notification mute, depending upon what you've got it set to it in Settings. The other function is controlled by the left-hand end of the iPad's taskbar : double-click the home button to open the taskbar at the bottom of the screen and swipe that to the left.
If it's the mute icon there (i.e. the side switch is controlling rotation) then does it have a line through it ? If it does then tap the icon to turn off mute.
If its the rotation icon (i.e. the side switch is controlling mute) then if it has a padlock in the middle of the icon then tap the icon and rotation lock should be turned off.