GIMP: Pango Error by using Text-Button

Hi,

I've the following problem:

All works fine, but if I want to add text to my picture and klick on the "A"-Button this errors come:

First:

Pango-ERROR **: Unable to open font file C:/WINDOWS/font/DejaVuSans.ttf for font DejaVu Sans 16, exiting aborting...

Second:

Runtime Error!

Program: H:\PortableApps\GIMPPortable\App\gimp\bin\gimp-2.4.exe

This application has requested the Runtime to terminate it in a unusual way. Please contact the application's support team for more information.

My Windows font folder is applied in the preferences under folders / fonts, but it would not help.

The font DejaVuSans.ttf is installed.

I don't know, why I can't use text.

Can someone help me?

Cincerely,

Aurelius