As Supernova9 says, the license limits concurrent users of the database at any one point in time.
If you're doing some sort of web based solution, then its very unlikely the number of concurrect connections to the database will be that high. Lets say 10 people have a page open, refreshing every 60 seconds. Unless all connect at the very same time then the chances are you'll only have one connection to the database at a time.
You could use some PHP script to limit access to the database to just one page loading at a time. Assuming most queries execute within hundredths of a second, then this wouldn't be a problem.
I'm not entirely sure if the license would allow this, as I'm a little confused with the license agreement.