Hi Friends,
I am having an issue with CRM 2011 Update rollup 18. When I try to add members to the marketing list using advanced find it is throwing an error. When I go and check the event logs on the CRM Server I found below warning
Can anyone please help on how to resolve this issue?

Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 17/09/2015 12:15:19
Event time (UTC): 17/09/2015 11:15:19
Event ID: 65f0aa26ab804b819b0facfca0cd0af8
Event sequence: 3096
Event occurrence: 3
Event detail code: 0
Application information:
Application domain: /LM/W3SVC/1/ROOT-1-130869602636106777
Trust level: Full
Application Virtual Path: /
Application Path: C:\Program Files\Microsoft Dynamics CRM\CRMWeb\
Machine name: Servername
Process information:
Process ID: 10556
Process name: w3wp.exe
Account name: Domain\Username
Exception information:
Exception type: TypeLoadException
Exception message: Could not load type 'Microsoft.Crm.Sdk.Messages.AddMembersByFetchXmlListRequest' from assembly 'Microsoft.Crm.Sdk.Proxy, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.
at Microsoft.Crm.Application.Pages.MA.ListAddPage.ConfigureForm()
at Microsoft.Crm.Application.Controls.AppUIPage.OnPreRender(EventArgs e)
at System.Web.UI.Control.PreRenderRecursiveInternal()
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
Request information:
Request URL: https://orgname.domainmame.co.uk:443/MA/Lists/ListQualificationdlg/dlg_List_add.aspx?iObjType=2&iOption=2&iTotal=0&iViewType=1039&isDirty=true&itemObjectId={468FC122-4C5C-E511-B8E1-00505685B69E}&itemObjectTypeCode=4300&sInvokeType=lqAdd&savedQueryId={00000000-0000-0000-00AA-000000666400}&savedQueryType=1039
Request path: /MA/Lists/ListQualificationdlg/dlg_List_add.aspx
User host address: 192.168.100.10
User: Domain\Username
Is authenticated: True
Authentication Type: Federation
Thread account name: domain\Username
Thread information:
Thread ID: 28
Thread account name: Domain\Username
Is impersonating: False
Stack trace: at Microsoft.Crm.Application.Pages.MA.ListAddPage.ConfigureForm()
at Microsoft.Crm.Application.Controls.AppUIPage.OnPreRender(EventArgs e)
at System.Web.UI.Control.PreRenderRecursiveInternal()
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
Custom event details:
Nemath