Ok, I must be a total moron...
I installed DownloadsII within days of setting up my forum last fall...it's been a dream... easy to use, easy to setup...and users were even using it ( a little).
However... yesterday, a user PMd me and said that uploads were reporting "Maximum Upload Limit Reached". It's the first file the user tried to upload that day, and the second he's ever attempted.
I also tried... and I get the same error... Downloading tells me I've exceeeded my daily limit.
Now I SWEAR there have been no setting changes. the DLII settings for my Administrator group is -1 down the line. The file I'm trying to upload (and download) is under 10k. The only change made to the forum settings since setup was going from 3.7.1 to 3.7.2 when that came out.
I have checked every setting I can find: DLII settings, Usergroup Settings, read the posts in here about how these problems are most commonly caused by settings at the host (which I had them check...goof with...and no change).
There are a grand total of 4 files in the file area totalling less than 35K.
I've got vbulletin v3.7.2 and DLII v5.0.8 and DLII Create threads v.1.0.2.
(Since my original post, I have upgraded to 5.1.0 and still the same problem...)

Alex, can I buy a clue for 100?