Solving equations in Matlab – results are different on different platforms

I am trying to solve a equation in Matlab. For example, assume solving quadratic equations. The problem I am facing is the results are not matching on different machines. I had stored a big file with the solutions and when run on my team members PC it gave slightly different results. Though the error is very negligible, the system cannot accept them because they are simply different. One is on Mac and another is on Windows 7. What are the known accuracy issues in Matlab? Can I post the code so that the code can also be verified? How to make the decision of Platform for Matlab so that the error will be zero all the time. Thank you for your reply.