Numerical solution for Ordinary diferential ecuation

[chire]

I started to solve some ordinary diferential ecuations (ODE) with matlab for some specific research topic.
im using the internal solver algorithm called ode45

i am not familiar with the advanced concepts of numerical methods so i ask the following.

is it possible that the numerical solution computes "wrong" and result should not be trusted??

ill explain myself, for an specific ODE ecuation, im getting a weird curve as the numerical solution. This does not happen on other simpler cases.

more specific: this is what im getting

http://dl.dropbox.com/u/6380744/untitled.jpg

plotted from 0 to pi/2.

as it approaches pi/2 it grows exponentially too fast for our context, and as consecuence the rest of the curve cannot be appreciated and looks flat.
we are not sure if this numerical solution can be trusted
any help or explanation, is thanked.

if you want to reproduce the case i can give you the ODE and the initial conditions