[AccessD] database locked by user admin at machine " " error

I have a database that resides on a netware 6 file server and serves
about 30 user across a wide area network.  All users belong to a group
that has full rights to the directory in which the database is located. 
Usually there will be three or four users trying to access the database
at the same time. 

Users access the data via  data access pages over the internet.  Some
days there are no problems with access to the database.  Other days if
even one user is already logged into the database a second user will get
the error message that  the database is locked by user admine at machine
"(machine name)".    Sometimes they will continue to get the message
even after the first user logs out of the the database.    Sometimes
they are able to open the access pages, but then are unable to enter
data.   Any suggestions or ideas as to what the problem may be?

Bonnie Snider, LAN Administrator
DWS North Admin
Phone:   526-9253
Cell:        430-1219
FAX:       526-9744
EMAIL:   bsnider at utah.gov