Adobe Flash Player Error #1009 Windows 8.1

I am running Windows 8.1 and since the last windows update on 9 August, I have started to see the following Flash Player error in IE11 when using a broadband speed test which has worked fine prior to 9 August. The error does not occur in Firefox.

TypeError: Error #1009: Cannot access a property or method of a null object reference.

at stremote/prepareProgress()

at flash.utils::Timer/_timerDispatch()

at flash.utils::Timer/tick()

I have no missing Microsoft updates.

How do I correct this error?

Many thanks

Keith