URGENT: After Production upgrade from 9.5.1 to 10.1 getting runtime errors

Specifically, stacks like this on all processes using Rumba:

at System.Windows.Forms.UnsafeNativeMethods.CoCreateInstance(Guid& clsid, Object punkOuter, Int32 context, Guid& iid)

   at System.Windows.Forms.AxHost.CreateWithLicense(String license, Guid clsid)

   at System.Windows.Forms.AxHost.CreateInstanceCore(Guid clsid)

   at System.Windows.Forms.AxHost.CreateInstance()

   at System.Windows.Forms.AxHost.GetOcxCreate()

   at System.Windows.Forms.AxHost.TransitionUpTo(Int32 state)

   at System.Windows.Forms.AxHost.CreateHandle()

   at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)

   at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)

   at System.Windows.Forms.AxHost.EndInit()

   at HostTools.frmTN3270Interface.InitializeComponent()