trouble configuring VLANs with 1800 switches

[dmp78]

Hello-
I've recently purchased a few 1800 series switches, and I am having trouble intergrating them into my environment. I currently have a 5304xl as my core switch, with about 10 2600 series switches at the edges. I have 6 VLANs setup, all working properly with the 2600's. On the 5304 and the 2600's, I tag all of my fiber ports with the necessary VLANs, and then untag the individual ports on the 2600's based on what VLAN I want them in.
Now, I'm having trouble getting my new 1800's to talk to the 5304. I'm sure that it's the different interface in the 1800 that's throwing me off.. I created 6 VLANs (1-6), and I set the fiber port (24) to "tagged only", and made it a member of all 6 VLANs. It is connected to a tagged port on the 5304, but I can't even ping between them.
Can someone help point me in the right direction here? Thanks for the help!

[Alan Clarkson]

As far as I remember VLAN 1 is forced as the management VLAN and if you aren't using this as untagged between switches it may be the cause.