spaces, uppercase characters, and numbers are messing up my md5 hash function

i am writing the md5 algorithm in python, it works just fine if the input string has nothing but lowercase characters. But when there are spaces, uppercase chars, and numbers the md5 hash isn't the same as what it should be(I am testing it against mysql) and the hashes in the md5 wikipedia article. Does anyone have any idea as to what is wrong? Is my os processing the characters differently than it should?I'm using a mac running osx leopard 64-bit. Any help would be appreciated.

You should post your code.