PDFCreator's Problem

PDFCreator runs from another program. PDF files doing perfectly, but in the time of creating PDF files, the focus gets lost to the working program.
I will try to explain you: user turns on the computer, runs some program (for example Windows Explorer), then runs our office program and creat PDF files in it. At this moment Windows Explorer is an active and  office program is visible in the background. After 2-5 seconds, Windows Explorer disappears, everything comes back to normal, PDF file is created. If running only our office program and no other, so there is no such effect. Always there is the interface of the program which runs directly in front of our office programs. It is very irritate and frighten users, because they think, that have done something wrong.
Please, give me advice, what i can do to remove this effect?