Good day, cricri49
No, the problem is not in Windows Media Fondation, but because of priority of components. WMP doesn't allow to use any another component in Windows 7, accept of ffdshow. So any other components disabled in WMP.
But here is solution.
We've prepared for you several steps you need to make for watching AVC video streams using Elecard AVC Plug In for WMP
1. Download two utilities Win7DSFilterTweaker_3_7.exe
Screenshots and DSFMgr.exe
following this linkhttps://members.elecard.ru/productloader/getfile.php?id=ahiltsrm_1293559199%2Favc_FOR_wmp.zip
2. Open Win7DSFilterTweaker_3_7.exe / then follow screenshots I made for you and in case system ask reboot, reboot PC.
3. Then try to open any AVC video by WMP. In case you see our logo, you access, in not then go to 4.
4. Open DSF manager / find there string Elecard AVC video Decoder (HD, SD). Then select by turn each filter and for each of it click Show filter properties
4.1 In filter properties move scrool up (as it shown DSF #1.jpg) to maximum FFFF0000
4.2 After you repeat operation for each filter, Close windows
4.3 Play video again
If you have any questions or I need to clarify, feel free to ask