Hi,
maybe it's just a permission issue: Top-Level-Folders must be shared with the virtual user "LAN" to be visible via DLNA. We did this for security reasons, so especially servers somewhere in the internet do not expose things by default.
If this doesn't solve the problem we need some more information like LimboMedia version, DLNA client(s) used and maybe some network information about your setup and LimboMedia startup log.