The first line of the code you suggest results in a null assignment to the variable a. After the curl is executed, evaluating the variable a returns nothing. Wrapping FullForm[] around it returns the word Null. Executing the curl instruction in a terminal window results in the error message:
curl: (58) unable to use client certificate (no key found or wrong pass phrase?)
I have no trouble accessing the site in question in any of the web browsers I've tried---even Firefox, which is pretty picky about such matters. And Mathematica has no trouble when I use it from a MacBook Air (that's too small for "production" use).
I'm at a loss to know what "SomeFunction" ought to be in this case.
I'm using Mathematica v8.0.4.0 on an iMac running OS X 10.7.5