Win32::OLE(0.1711) error 0x800a03ec in METHOD/PROPERTYGET "Open"

I have an applications which uses a combination of Win32::Ole and perl to open some .xlsm files and read informations from them.
The application worked Friday, but today it started to crash throwing the message:

OLE exception from "Microsoft Excel":
Unable to get the Open property of the Workbooks class Win32::OLE(0.1711) error 0x800a03ec
    in METHOD/PROPERTYGET "Open" at myscript.pl

and the line that crashes is : $xlsApp->Workbooks->Open( $workbook_path).

The execution leaves a trailing EXCEL.exe process. If I kill and delete the temporary *.xlsm file which is created when the Win32::Ole tries to read the file, the next execution throws another one:

Win32::OLE(0.1711) error 0x8001010a: "The message filter indicated that the application is busy" in METHOD/PROPERTYGET "Worksheets"

What I found suspect was actually this update, which states

Installing this update may cause applications based on the Microsoft JET Database Engine (Microsoft Access 2007 and older or non-Microsoft applications) to fail when creating or opening Microsoft Excel .xls files.

Does anyone know if there is a real issue or do you know a workarround for this situation?