When using a Windows machine as the webMathematica server, the error message FrontEndError: ExportString failed: -Graphics- may appear in place of the graphics on a webpage. This may indicate that the Mathematica front end did not launch.

Windows limits the amount of memory allocated to non-interactive users, such as Mathematica kernels launched by the Tomcat server. When such kernels need to perform a calculation that requires the Mathematica front end, the memory allocation setting may prevent the launching of the front end.

To increase the available memory, allow non-interactive users to use the same amount of memory as interactive users:

1. Locate the registry entry:

   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\
   SubSystems\Windows
   
   %SystemRoot%system32csrss.exe ObjectDirectory=Windows
   SharedSection=1024,3072,512 Windows=On SubSystemType=Windows
   ServerDll=basesrv,1 ServerDll=winsrv:UserServerDllInitialization,3
   ServerDll=winsrv:ConServerDllInitialization,2 ProfileControl=Off
   
   MaxRequestThreads=16 

2. Identify the SharedSection variable.
3. Delete its third parameter, i.e. replace “1024,3072,512” with “1024,3072” in the above example.