The problem lies in the /tftpboot directory of the boot server. Confirm that the HOSTID and HOSTID.ARCH files are linked to the correct inetboot.* file for your architecture. The following is an example of how a symbolic link should look:
# cd /tftpboot # ls -l 81971904* 81971904 -> inetboot.sun4m.Solaris_2.4 81971904.SUN4M -> inetboot.sun4m.Solaris_2.4 |