If the cassette section is not a 'must have', and a simple cleaning of the laser in the CD section doesn't fix it, you should probably find a willing landfill or electronics recycler. I don't know what the 'dn' error code means......
Do you keep any music on your computer? I-tunes or any of a bunch of other programs, many free, will allow you to put your CDs on the computer and either go the Ipod / Dock way or more elaborate 'music server' route. The 'pod method will easily exceed cassette fidelity and the 'pod is very portable and will stay with you anywhere.