Parser error

[sandy]

Parser Error
Description: An error occurred during the parsing of a resource required to
service this request. Please review the following specific parse error
details and modify your source file appropriately.

Parser Error Message: The located assembly's manifest definition with name
'Microsoft.Web.UI.WebControls' does not match the assembly reference.

Source Error:


Line 5:
Line 6: <%@ Register tagprefix ="BTL" assembly="CustomControl"
NameSpace="BTLIntraPageDesignLayout" %>
Line 7: <%@ Register TagPrefix="IE"
Namespace="Microsoft.Web.UI.WebControls"
Assembly="Microsoft.Web.UI.WebControls, Version=1.0.2.226, Culture=neutral,
PublicKeyToken=31bf3856ad364e35" %>
Line 8:
Line 9:

Help needed.

Thanks.
Sandy