Could not load file or assembly 'GCheckout' or one of its dependencies

I just unzipped nopCommerce_1.90_Source.zip and opened solution in Visual Studio 10.0. I don't have any compilation error, but its failing in browser with following error.

I checked GCheckout.dll is available in Dependencies folder. It should not be in GAC as it is not a signed assembly. Any one has experienced this error before, and let me know if solution exists.

[FileLoadException: Could not load file or assembly 'GCheckout' or one of its dependencies. The parameter is incorrect. (Exception from HRESULT: 0x80070057 (E_INVALIDARG))]

[FileLoadException: Could not load file or assembly 'GCheckout, Version=1.3.2.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The parameter is incorrect. (Exception from HRESULT: 0x80070057 (E_INVALIDARG))]
   System.Reflection.RuntimeAssembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks) +0
   System.Reflection.RuntimeAssembly.nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks) +39
   System.Reflection.RuntimeAssembly.InternalLoadAssemblyName(AssemblyName assemblyRef, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection, Boolean suppressSecurityChecks) +132
   System.Reflection.RuntimeAssembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) +144
   System.Reflection.Assembly.Load(String assemblyString) +28
   System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +46

[ConfigurationErrorsException: Could not load file or assembly 'GCheckout, Version=1.3.2.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The parameter is incorrect. (Exception from HRESULT: 0x80070057 (E_INVALIDARG))]
   System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +618
   System.Web.Configuration.CompilationSection.LoadAllAssembliesFromAppDomainBinDirectory() +209
   System.Web.Configuration.CompilationSection.LoadAssembly(AssemblyInfo ai) +130
   System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection compConfig) +178
   System.Web.Compilation.BuildManager.GetPreStartInitMethodsFromReferencedAssemblies() +94
   System.Web.Compilation.BuildManager.CallPreStartInitMethods() +332
   System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException) +591

[HttpException (0x80004005): Could not load file or assembly 'GCheckout, Version=1.3.2.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The parameter is incorrect. (Exception from HRESULT: 0x80070057 (E_INVALIDARG))]
   System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +8946484
   System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +97
   System.Web.HttpRuntime.ProcessRequestInternal(HttpWorkerRequest wr) +258