[Dev-C++] Debugger Problem

Hello,
I have wrapped an image library to make it Object Oriented, and now my 
static library is called vImage.lib (the library which is based on is 
instead a dll). Now, to test the library I have this example file in a 
new project, and I cannot debug it. It just doesn't perform the 
step-by-step debug.
To check if the project settings were ok I also used the "hello" example 
and pasted my code in it. Result: when I don't link to my library, 
everything worsk fine, as soon as link to it, it doesn't debug anymore.
Note that the problem doesn't affect only the code based on my library, 
but all the code (i.e. also the one of the "hello" example that worked 
before)
Note also that I have activated the generation of debug info when 
compiling the library as well.
What can I do?
thank you_ricky