I have 4 partitions on my hdd:
hda1 - primary - linux ext3
hda2 - primary - linux swap
hda3 - primary - fat32 - win 98
hda5 - logical - fat32
hda6 - logical - fat32
I have windows XP on hda5 but I don't know to make it start. If I add
other = /dev/hda5
label = WinXP
table = /dev/hda
in lilo.conf I get an error when I run lilo.
Could you help me to add Windows XP?
Thanks!

what is the output of lilo? what is the error ?

ps: check with the label between quotes like this: label="WinXP". But I'm not conviced it will be sufficent.

The output of lilo is: Partition entry not found.

I think you should past your entire lilo.conf here.

# LILO configuration file
# generated by 'liloconfig'
#
# Start LILO global section
boot = /dev/hda
append = "hdc=ide-scsi"

bitmap = /boot/lilo.bmp
bmp-colors = 1,,0,2,0
bmp-table = 120p,173p,1,15,17
bmp-timer = 254p,432p,1,0,0

default = Linux_Slackware

prompt
timeout = 50
# Override dangerous defaults that rewrite the partition table:
change-rules
reset
# VESA framebuffer console @ 1024x768x256
# vga = 773
# Normal VGA console
# vga = normal
# VESA framebuffer console @ 1024x768x64k
vga=791
# VESA framebuffer console @ 1024x768x32k
# vga=790
# VESA framebuffer console @ 1024x768x256
# vga=773
# VESA framebuffer console @ 800x600x64k
# vga=788
# VESA framebuffer console @ 800x600x32k
# vga=787
# VESA framebuffer console @ 800x600x256
# vga=771
# VESA framebuffer console @ 640x480x64k
# vga=785
# VESA framebuffer console @ 640x480x32k
# vga=784
# VESA framebuffer console @ 640x480x256
# vga=769
# End LILO global section
# Windows bootable partition config begins
other = /dev/hda3
label = Windows
table = /dev/hda
# Windows bootable partition config ends
# Linux bootable partition config begins
image = /boot/bzImage-2.6.7-custom
root = /dev/hda1
label = Linux_Slackware
initrd = /boot/initrd.splash
append = "splash=silent"
read-only
image = /boot/vmlinuz
root = /dev/hda1
label = Linux
read-only
other = /dev/fd0
label = floppy
unsafe
# Linux bootable partition config ends

You did everything allright. I think you just missed the right /dev/.

other = /dev/hda5 -> Partition entry not found means that /dev/hda5 do not refer to any partition..

I'm not sure, but you should check your partition table and see who's who

I don't think Windows is all that thrilled about being booted from an extended partition. I believe you need to work a little magic since Windows thinks it's the one and only OS, so why would you ever consider putting it out there in an extended partition?

The best tutorial I've found on multibooting, including booting Windows from an extended partition, is at http://www.goodells.net/multiboot/ This tutorial will explain how multibooting works, not give you a step-by-step guide. I've never booted Windows from an extended partition myself, but that exact issue is included in the tutorial.