Undefined symbol in executing time

[Isabel Gil]

Hello PETSc's users!

I am trying to use PETSc for the first time along with another library. 
I compile my program without any problem but when I try to execute it, 
in a parallel way, I obtain the following error:
"symbol lookup error: 
/path_where_PETSc_is_installed/petsc-2.2.1/lib/libg_c++/linux-gnu/libpetscmat.so: 
undefined symbol: PETSC_COMM_SELF"

I have used the command "nm" and ,effectively, this symbol is undefined. 
I don't really know where the problem is. I am using version 2.2.1

Any help and advice will be welcome
Thanks in advance
Isa