I'm Confused

So I followed the guide... But for some reason I can't restore the databases -_-

I tried everything I know and I honestly just can't figure it out.
I keep getting:

Code:

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TITLE: Microsoft SQL Server Management Studio Express
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An exception occurred while executing a Transact-SQL statement or batch. (Microsoft.SqlServer.Express.ConnectionInfo)

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ADDITIONAL INFORMATION:

The media family on device 'C:\Database\Account.bak' is incorrectly formed. SQL Server cannot process this media family.
RESTORE HEADERONLY is terminating abnormally. (Microsoft SQL Server, Error: 3241)

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If anyone could help me I would be grateful. Thanks.