I had recently installed SQL server 2012 and I used mostly the default settings. Database works fine and I can happily connect using SSMS (SQL Server Management Studio) but
You should check to see what user the SSIS Service is running under. Go to Start > Run > Type "services.msc" and scroll down to the SQL Server Integration Services 11.0 entry. Right click and check the properties to find out what user it's running under. The second tab should be the LogOn tab. Since you're just running on a local instance, you can set your user as the LogOn User account and SSIS will have the same permissions that you do.