/usr/src/redhat/SOURCES is for unpacked (installed)
".src.rpm" packages. The kernel source will be in
/usr/src/kernels/linux-2.6.15... , so please install
package 'kernel-devel' (or kernel-source)
e.g. 'kernel-devel-2.6.15-1.2054_FC5.i686.rpm'
http://rpm.pbone.net/index.php3/stat....i686.rpm.html
and find
linux-2.6.15.../drivers/net/e1000/
Regards