How to convert Pycorder files into gdf files

[BrainSup]

Hello,

I have the following question: how to convert a file saved in Pycorder into a format that is able to be read by OpenVibe?
I have an ActiChamp and OpenVibe for Brain Products.
I have tried to convert it by using the box Brainamp File Reader connected to GDF file writer (and Timeout and Player controller). The file we want to convert has .vhdr extension.
When I run it some errors appear as shown in Picture attached. Could anyone help me please?

Thank you,
Silvia Takey