hello everybody

can anybody tell me the max no. of connection possible in dedicated server mode if one has got 15 user license .
its workgroup server version of oracle 8.1.5 and nt 4.0

my db was running in mts mode ,i saw ora-04031 frequently.
i have 512 mb ram with sga -170mb .i had 5 shared server processes and 2 dispatchers.to get rid of that problem

I changed the db to dedicated server mode.now it run well for 5 days then problem started more users cannot connect simultaneously.can anybody figure out ??