perhaps anyone has a hint for a newbie?

For using my remote control (Old Twinhan Remote) on ProgDVB 4.84 I'm using winlirc (newest) and winlirc-client (Vers:1.05,API 1.32). Without started ProgDVB the remote control and winlirc server works fine. Everey command is quickly interpreted and indicated by the green button in systemtray. But when ProgDVB is started I must press the Remotecontrol button 3 to 4 times until the command is taken by ProgDVB (e.g. the indicator button in systemtray changes to green).
For me it seems that ProgDVB makes a so high utilisation on computer (not CPU, because it runs only at 20-30%) that the remote receiver can't receive or forward the command from the remote.
Trying to set winlirc to "realtime" and ProgDVB to "lowest" Priority in Taskmanagerlist are without any noticeable effect. Using another remote also without noticeable effect.
On a other system with a VIA C7 processor, the Remote control is nearly unusable by this effect.
Has anyone a idea how I can solve this problem?
Thanks and regards
MaBoben