Not sure if this is a bug or if i am doing something wrong......

I am using the control in timetable view back to a sql database with multiple users add and editing data in the database all the time, when an item is selected in the control I need to check that the record is not in use by other users in my database so I use the  ItemSelecting Sub I check with my database to see if the item is in use and if so then stop the user from editing the item in the control by using e.Confirm = False, the problem is if you try and change the size of the item after I cancel it with e.Confirm = False the mouse icon stays as the move icon and you have to click the control or forum before the mouse icon will refresh. I have tried Me.Cursor = cursors.Default and me.refresh below is my code..... Please help


    Private Sub cal1_ItemSelecting(ByVal sender As Object, ByVal e As MindFusion.Scheduling.WinForms.ItemConfirmEventArgs) Handles cal1.ItemSelecting


       If _Locked.Locked = True Then
           cal1.ResetDrag()
           MsgBox("this is locked by:" & _Locked.Lock_By & " on the: " & _Locked.lock_date)
           e.Confirm = False

       End If
       app = Nothing
       rec = Nothing
       Me.Cursor = Cursors.Default
       Me.Refresh()

    End Sub

I installed this version.   
Deleted my obj and bin folders for my project. Referenced the new dll in project references. 
Cleaned the solution. 
but when I goto build the solution I get error
 
Error6'The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)' 
 
Please can you help? 

They only way that I could fix this was to create a new project and then import all of my forms into it and re-reference to the .dll, Is there an easier way to fix this?