Resolution:
SecureRecon 4.0.3 requires mono. Please see notes below for installing mono on RHEL 5.
Mono install on RHEL/Centos 5
yum install gcc glib2-devel bison libX11-devel freetype-devel fontconfig-devel gcc-c++ libpng-devel
tar -xvf libgdiplus-2.6.7.tar.bz2
cd libgdiplus-2.6.7
./configure --prefix=/usr/local; make; make install
sh -c "echo /usr/local/lib >> /etc/ld.so.conf"
/sbin/ldconfig
cd ..
tar -xvf mono-2.6.7.tar.bz2
cd mono-2.6.7
./configure --prefix=/usr/local; make; make install
nano ~/.bashrc
And add the following lines at the end:
PATH=/usr/local/bin:$PATH
LD_LIBRARY_PATH=/usr/local/lib/:$LD_LIBRARY_PATH
PKG_CONFIG_PATH=/usr/local/lib/pkgconfig:$PKG_CONFIG_PATH
bash
mono -V