after upgrade sql and deploying the files gives an object reference in pluginmanager for nop 2.5

Here is the stack trace! I follow the instructions on upgrade note. What should i do?


best regards,
mft2010


Object reference not set to an instance of an object.
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.NullReferenceException: Object reference not set to an instance of an object.

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.  

Stack Trace:


[NullReferenceException: Object reference not set to an instance of an object.]
   Nop.Core.Plugins.PluginManager.PerformFileDeploy(FileInfo plug) in C:\Users\senay\Documents\Visual Studio 2010\Projects\nopCommerce_2.50_Source\Libraries\Nop.Core\Plugins\PluginManager.cs:289
   Nop.Core.Plugins.PluginManager.Initialize() in C:\Users\senay\Documents\Visual Studio 2010\Projects\nopCommerce_2.50_Source\Libraries\Nop.Core\Plugins\PluginManager.cs:127

[Exception: Object reference not set to an instance of an object.
]
   Nop.Core.Plugins.PluginManager.Initialize() in C:\Users\senay\Documents\Visual Studio 2010\Projects\nopCommerce_2.50_Source\Libraries\Nop.Core\Plugins\PluginManager.cs:183

[InvalidOperationException: The pre-application start initialization method Initialize on type Nop.Core.Plugins.PluginManager threw an exception with the following error message: Object reference not set to an instance of an object.
.]
   System.Web.Compilation.BuildManager.InvokePreStartInitMethods(ICollection`1 methods) +11712062
   System.Web.Compilation.BuildManager.CallPreStartInitMethods() +465
   System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException) +1167

[HttpException (0x80004005): The pre-application start initialization method Initialize on type Nop.Core.Plugins.PluginManager threw an exception with the following error message: Object reference not set to an instance of an object.
.]
   System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +11700992
   System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +141
   System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +4869221