Toad for DB2 suddenly stopped connecting to databases

Toad has been working fine for several months, recently it started giving me the messages below. Sometimes restarting helped, sometimes not. Now it will not connect at all… Any suggestions? I have uninstalled and reinstalled but still get the same messages

System.IO.FileLoadException
A procedure imported by ‘Quest.Data.DB2.Admin.dll’ could not be loaded.
Stack Trace:
at Quest.Toad.DB2.DB2ConnectionControl.RefreshUILocal(ConnectMediator connectOptions)
at Quest.Toad.DB2.DB2ConnectionControl.RefreshUI(ConnectMediator connectOptions)
at Quest.Toad.DB2.DB2ConnectionControlSwitch.RefreshUI(ConnectMediator connectOptions, ConnectionFormStyle displayStyle)
at Quest.Toad.ConnectionManager.ConnectionPropertiesControl.Refresh(ConnectMediator connOptions)
at Quest.Toad.ConnectionManager.ConnectionPropertiesControl.AssignConnectOptions(Node node, ConnectionFormStyle style)
at Quest.Toad.ConnectionManager.ConnectionForm.RefreshUI()
at Quest.Toad.ConnectionManager.ConnectionControl.RaiseFocusChanged(Node node)
at Quest.Toad.ConnectionManager.ConnectionControl.connectionList_FocusedNodeChanged(Object sender, FocusedNodeChangedEventArgs e)
at DevExpress.XtraTreeList.TreeList.RaiseFocusedNodeChanged(TreeListNode oldNode, TreeListNode newNode)
at DevExpress.XtraTreeList.TreeList.InternalSetFocusedRowIndex(Int32 newFocusedRowIndex)
at DevExpress.XtraTreeList.TreeList.InvokeSelectionAction(Action action)
at DevExpress.XtraTreeList.Handler.TreeListHandler.TreeListControlState.ChangeSelection(RowInfo pressRowInfo, Boolean isLeftButton)
at DevExpress.XtraTreeList.Handler.TreeListHandler.NodePressedState.Init()
at DevExpress.XtraTreeList.Handler.TreeListHandler.SetControlState(TreeListState state)
at DevExpress.XtraTreeList.Handler.TreeListHandler.NormalState.OnPressNode()
at DevExpress.XtraTreeList.Handler.TreeListHandler.NormalState.MouseDown(MouseEventArgs e, TreeListHitTest ht)
at DevExpress.XtraTreeList.Handler.TreeListHandler.OnMouseDown(MouseEventArgs e)
at DevExpress.XtraTreeList.TreeList.OnMouseDown(MouseEventArgs e)
at Quest.Toad.TreeList.ToadTreeList.OnMouseDown(MouseEventArgs e)
at System.Windows.Forms.Control.WmMouseDown(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at DevExpress.XtraEditors.Container.EditorContainer.WndProc(Message& m)
at DevExpress.XtraTreeList.TreeList.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Seems something changed in your environment.
It would be helpful to give us more information.

What version of Toad DB2 are you running?
What version of the IBM DB2 client are you running?
What Windows OS are you running?
What .Net Framework version are you running?
Have you recently installed or uninstalled your DB2 client, .Net Framework or Toad DB2?