If the phone has an active Internet connection you can use the forget PIN feature. A PIN will be emailed to the Google/Gmail account which you can use to unlock the phone.
If this solution does not appy here, please connect the phone to the computer and download Android SDK tools along with SDK Platform tools when you start SDK Manager. Start a Command Prompt and type adb shell followed by rm /data/system/gesture.key. Reboot the phone and you will have access because you can enter any pattern and the phone will unlock.
If this still does not work, I believe you will need to Factory Reset the phone from the Recovery menu. To enter Recovery, pull out the stylus and press Volume Up + Home Menu + Power button.