RMVB to DVD Problems

I have a RMVB video file that my church gave me to put on DVD. Since I’ve been doing some work for the church, I thought I’d give it a try. First problem I had, was I had no converter software, so I went and got ‘Cucusoft MPEG/AVI to DVD/VCD/SVCD/MPEG Creator (Pro Version)v7.07’ to do the job. Well after it created the ISO file and burnt to DVD I put it into a Stand Alone DVD player, the picture seemed to be jerky. What did I do wrong? Please help a lonely, desperate, ol man!
Thanks
Nick