Crystal reports log4net

I am using Visual Studio 2010 and the reports run fine on my local machine but when i deploy my web application on the server, i get the log4net error.

can anyone help me out with what i am missing?

thanks

the error is as below

Could not load file or assembly 'log4net, Version=1.2.10.0, Culture=neutral, PublicKeyToken=692fbea5521e1304' or one of its dependencies. The system cannot find the file specified.

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.IO.FileNotFoundException: Could not load file or assembly 'log4net, Version=1.2.10.0, Culture=neutral, PublicKeyToken=692fbea5521e1304' or one of its dependencies. The system cannot find the file specified.

Source Error:

Line 15:     <form id="form1" runat="server">
Line 16:     <div>
Line 17: <CR:CrystalReportViewer ID="viewSheet" runat="server" Line 18:             AutoDataBind="true" EnableDatabaseLogonPrompt="False" 
Line 19:             EnableParameterPrompt="False" ReuseParameterValuesOnRefresh="True"