When converting the attached power point to PDF, red artifacts are present in the texbox as a result of the conversion. This behavior was observed using Redhat 5.3 linux and version 7.3.0 of the java library.
I have worked with the presentation file shared and have not been able to observe the issue specified when using Windows 7. I have shared the generated PDF with you as well in this regard. Please share the generated PDF on your end as well by highlighting the issue.