Change in use of basic (uno) api since version 5.1?

Hi all,

I use basic scripts in our ERP system to open, create, modify, etc. Calc documents.
This worked fine with LibreOffice for years till version 5.1.

The LO-part of the scripts start with the line 

  Set oServiceManager = CreateObject( "com.sun.star.ServiceManager" )

With LO version 5.1 this line produces an error (Err.Number is -2147418113, F8000FFFF). 
There are no changes in the ERP system nor in the scripts, everything still works fine on machines 
with LO 5.0. Only the machines with LO 5.1 have this problem.

I couldn't find anything related in the release notes for version 5.1. 
What has changed and what can I do to get the scripts working again with LibreOffice?


Winfried