After installing some distros and search again and again in the net, IMHO:
-Kernels 2.4.x usually don't work with this motherboard (k7vmm): distros like Red Hat 8, Mandrake 9.0, Debian 3.0 with kernel 2.4.x and Debian based ones with kernel 2.4.x, Lycoris...
I could only boot Suse 8.0 (kernel 2.4.18-4GB), Debian 3.0 with kernel 2.2.20 and Yoper.
-Bad support of ECS, specially in this motherboard. BIOS of model k7vmm+ (similar but more modern than k7vmm) has been updated to fix this problem but k7vmm has last BIOS update on August 2002, and ECS didn't give a solution about this problem.
So, the only way is to change the motherboard or to wait to see if new kernels support this stupid motherboard.