64K file size limit on Websphere

I am trying to deploy files to a clustered WAS environment. Every time I try to drag a file larger than 64K to the file system, I get an internal stack 0 error. I cannot save files larger than 64K. If I deploy a file smaller than 64k, then add images to the file such that it grows to a size larger than 64K, I get an error message that prevents me from saving the file. The environment is AIX, Websphere, DB2 on an IBM iSeries LPAR. Any suggestions on where to look to start to troubleshoot this issue?