[Users] trouble with pci passthrough

hi everybody i have trouble with pci passthrough of a parallel port adapter. I need this for a key dongle. The Server is a single machine and i want to use them with the all-in-one plugin from ovirt. I do some tests with: Fedora 17, CentOS6.3, Oracle Linux 6.3 latest kernel, qemu-kvm and libvirt from repos. No extras or advanced configurations. Only a simple standard Server. I install "yum groupinstall virtualization" + virt-manager and some other. I configure iommu, modul blacklist and some other. Then i starting a Windows Server 2003 and assign the parallel adapter to the running server. I look in the device manager and found the adapter card. The dongle work finde and the Datev Lizenz Service are online. .. so far so good but when i install on the same Server ovirt. With same kernel qemu-kvm and libvirt! And i attach the adapter card to the windows server 2003 look in the device manager and found the card with a error "device cannot be start (code 10)" I am now looking for several days after the error and have diverse tried but I can not keep going. can someone help me? Thanks & greetings Andreas