I don't know if my portfolio is or isn't up to scratch, I always hope it is and I'm always updating it and fiddling with it in the hopes of making it better. I don't want to come across as an amature either! I spent a long time applying for jobs without including samples, then I tried by including examples in general and then job specific examples in the hopes of finding some kind of formula or technique that would work. Thusly all I seem to be getting is "we like your work but you're just not right..." "unfortunately we're not looking for anyone right now" "It's just not our style." etc etc etc.
*bangs head on desk*
I had a look at the pictures you uploaded to this site on your profile and part of your problem is that compared to the industry professionals in illustration you are a long way off the pace at the moment. Obviously you are starting out and no one is expecting you to to be perfect right away. If you haven't already make an account on CGHub or CGsociety or even conceptart.org (though they are less newbie/none pro friendly) They will help you improve as an artist and your logos will subsequently improve.
Your work also has odd pixelated lines, are you using ms paint? Because if you are serious about doing freelance work you need to invest in a program that will allow you to do vector graphics like Illustrator or Photoshop which will give you a much better finish. If you give me a link to your portfolio will have a look at it and see if can see where you can improve it