(can pull up using: www.../?q=alias, but cannot using the preferred www.../alias)

They all worked fine for the longest time.
Now, trying to pull up any URL that is aliased just dumps to the homepage.
The only recent admin change I made was adding the webform.module, but disabling it doesn't revert the path alias to working.

hmm...
any help?
Clients need to access these "private" pages, and can't through the aliased URL.

I've checked permissions, et al.
The alias admin page lists all the correct paths.
thanks!