Welcome to justanswer.
Are you getting th option of lost password?
Try entering your google account information i.e. the password XXXXX your google account.
If still it says incorrect password XXXXX you will have to hard reset your Tab but this will erase your data.
But the content saved on your memory card will not be lost.
As long as you have a Google account synced to your device, your contacts, calendar, etc. will be re-synced to the device after you run the initial setup again as long as you sign in with the same Google/Gmail account (as long as they were synced previously). Any apps you have paid for, you can get back after you reset the device by opening the Play Store, pressing Menu on the phone and choosing "My Apps".
To complete a Factory Reset follow these directions:
Please rate the solution positively. Or revert back if you need further assistance. Cheers. Regards Nathan.
Please reply back if the issue is solved or not.