Problem uploading files larger then 45K

I am new to Mysql and the use of servelets. I use Apache 1.3.9 for Win98 and Apache JServ 1.0. I have a basic servlet that is uploading files that I am storing in my database. Everything works fine if the file is less then about 45K or so. But for the larger files I got some errors such as java.lang.NullPointerException or java.lang.OutOfMemoryError. Is there anything to specify in the configuration of web server or servlets server to accept larger files? Thanks for the help!