Virtual Devices - Is there a MAX #?

We have been getting the following message a lot in the last two days.

SSP0134    Escape                  99    03/06/02   10:32:07   QEXSIGN
QSSP        0CC0     SIGNON       SYSTEM       0056
    Message . . . . :   Work station QPADEV00F7 is not known to S/36
environment #LIBRARY.

    Cause . . . . . :   You are requesting a System/36 environment
function from a display station that is not defined to the System/36
environment. Recovery. . . :   Use the CHGS36 command to add display
stations to the System/36 environment.

 CPA0701    Inquiry                 99    03/06/02   10:32:07   QCLXERR
QSYS        00C6     *EXT                      *N
    Message . . . . :   SSP0134 received by SIGNON at 4100. (C D I R)

    Cause . . . . . :   Control language (CL) program SIGNON in library
SYSTEM detected an error at statement number 4100. Message text for
SSP0134 is:    Work station QPADEV00F7 is not known to S/36 environment
#LIBRARY. Recovery . . :   This inquiry message can be avoided by
changing the program.
Monitor for the error (MONMSG command) and perform error recovery within
the
program. To continue, choose a reply value. Possible choices for
replying to


At this point the user is unable to signon (system ends the session
abnormally).  I know this workstation is valid though, because I can do
a WRKACTJOB and see it.  Of course, when I look out there now, the
workstation is assigned to another user.
Does the sys36 environment have a maximum number of sessions parameter?

TIA
Pat