Sql-server – Could not load file or assembly ‘Microsoft.SqlServer.DTSRuntimeWrap’

I can't figure out why I'm getting this error when I run my application (MVC 3). The project has a reference to Microsoft.SQLServer.ManagedDTS. I have both SQL Server 2008 R2 and SQL Server 2012 (both Express) installed. I'm using 2012 with this application.

Server Error in '/' Application.

Could not load file or assembly 'Microsoft.SqlServer.DTSRuntimeWrap'
or one of its dependencies. An attempt was made to load a program with
an incorrect format.

Description: An unhandled exception occurred during the execution of
the current web request. Please review the stack trace for more
information about the error and where it originated in the code.

Exception Details: System.BadImageFormatException: Could not load file
or assembly 'Microsoft.SqlServer.DTSRuntimeWrap' or one of its
dependencies. An attempt was made to load a program with an incorrect
format.

Source Error:

An unhandled exception was generated during the execution of the
current web request. Information regarding the origin and location of
the exception can be identified using the exception stack trace below.

Assembly Load Trace: The following information can be helpful to
determine why the assembly 'Microsoft.SqlServer.DTSRuntimeWrap' could
not be loaded.

WRN: Assembly binding logging is turned OFF. To enable assembly bind
failure logging, set the registry value
[HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1. Note: There
is some performance penalty associated with assembly bind failure
logging. To turn this feature off, remove the registry value
[HKLM\Software\Microsoft\Fusion!EnableLog].

Stack Trace:

[BadImageFormatException: Could not load file or assembly
'Microsoft.SqlServer.DTSRuntimeWrap' or one of its dependencies. An
attempt was made to load a program with an incorrect format.]
System.Reflection.RuntimeAssembly._nLoad(AssemblyName fileName, String
codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint,
StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean
forIntrospection, Boolean suppressSecurityChecks) +0
System.Reflection.RuntimeAssembly.InternalLoadAssemblyName(AssemblyName
assemblyRef, Evidence assemblySecurity, StackCrawlMark& stackMark,
Boolean forIntrospection, Boolean suppressSecurityChecks) +567
System.Reflection.RuntimeAssembly.InternalLoad(String assemblyString,
Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean
forIntrospection) +192 System.Reflection.Assembly.Load(String
assemblyString) +35
System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String
assemblyName, Boolean starDirective) +123

[ConfigurationErrorsException: Could not load file or assembly
'Microsoft.SqlServer.DTSRuntimeWrap' or one of its dependencies. An
attempt was made to load a program with an incorrect format.]
System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String
assemblyName, Boolean starDirective) +11568160
System.Web.Configuration.CompilationSection.LoadAllAssembliesFromAppDomainBinDirectory()
+485 System.Web.Configuration.AssemblyInfo.get_AssemblyInternal() +79 System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection
compConfig) +337
System.Web.Compilation.BuildManager.CallPreStartInitMethods() +280
System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager
appManager, IApplicationHost appHost, IConfigMapPathFactory
configMapPathFactory, HostingEnvironmentParameters hostingParameters,
PolicyLevel policyLevel, Exception appDomainCreationException) +1167

[HttpException (0x80004005): Could not load file or assembly
'Microsoft.SqlServer.DTSRuntimeWrap' or one of its dependencies. An
attempt was made to load a program with an incorrect format.]
System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +11700896
System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context)
+141 System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest
wr, HttpContext context) +4869125