Strange Compile Error at startup

I've been making use of this UDF http://www.ozgrid.com/VBA/ExtractNum.htm in one of my workbook for several years with no error.

My Excel workbook was made in version 1997-2003 and have been making use ot it on higher MS-Office version with no problem all these years.

Suddenly today when i am opening my Excel workbook, i get following error message at startup

Compile Error
 Automation Error

at start line only which is

Function EN(rCell As Range, _
     Optional Take_decimal As Boolean, Optional Take_negative As Boolean) As Double

When i ignore the message, (click Ok), UDF continue work well but such error message on start up annoys? What possibly could have gone wrong, and how to avoid such messages, as in past, there was no such error message.

Likewise, in another workbook, same error as quoted above comes in one of the macro which starts like

Sub SortData(ByRef Destination As Range, ParamArray SourceData())

Re: Strange Compile Error at startup

I'm reading https://support.microsoft.com/…ce-system-august-14,-2012

https://social.msdn.microsoft.…oft-patching?forum=isvvba

https://answers.microsoft.com/…51-4fd6-8aa1-2bce1dd2b1da