Though this discussion is more than 7 years old, fwd-bwd, you saved my day today. I replaced the freewheel of my Strida 5 today, but after reassembly, the rear wheel stopped turning. Then I read this discussion, and noticed that the new alloy freewheel was touching the bike frame because of the extra thick protrusion towards the brake disc. After removing the washer between the brake disc and the freewheel, the rear wheel started turning very very smoothly.
I just wanted to leave this comment to thank fwd-bwd and just in case someone else experiences the same problem.