Windows shares not showing up in finder

[AgentMax]

Hi!

First of all, i apologize for my bad english. I'm from Germany so it's not my native language

My problem:
As I upgraded to OS 10.5.0 I was able to see all my Windows computers in my finder sidebar listed under shares.
After the update, I think it was .1 or .2, they disappeared. And I have never seen them again.
I'm able to connect to these computer with connect to server in the finder menu (smb://IP).

I searched the whole web, found some stuff that I had to change on the windows machines (all Vista) but nothing helped.

If I install OSX Server 10.5.0 inside VMware Fusion 2 all shares are back again. Installing 10.5.5 = all shares are gone.

Bonjour shares are displayed.

Here's my network configuration:

Fritzbox 7170:
- managing Internet Access
- 192.168.0.1
- DHCP Server

connectet with Powerline:

Fritzbox 7270:
- WLAN b/g/n 2,4 Ghz WPA/WPA2
- 192.168.0.2
- using Fritzbox 7170 as DHCP and DNS Server

connected with LAN to:

Apple Time Capsule 500GB:
- WLAN n 5 GHz WPA/WPA2
- 192.168.0.3
- using Fritzbox 7170 as DHCP and DNS Server

Network client (all within the same workgroup):

1. Fritzbox:
- Canon MX850 LAN
- Powerline LAN

2. Fritzbox:
- Powerline LAN
- Wii WLAN
- XBOX360 WLAN
- PS3 WLAN
- iPhone 3G WLAN
- 2 PSP WLAN
- Airport Express WLAN
- Inspiron Laptop WLAN
- NabazTagTag WLAN

Time Capsule:
- Apple TV LAN
- HP Quadcore LAN
- MacBook Pro WLAN

Any suggestions?
Thanks