Hi Guys,
I know this is an old post but recently I had the same issue and note number 1276704 - jload export fails with java.lang.OutOfMemoryError. solved my issue.
log on to configtool and click on secure store and then on the right side of the screen click on URl and in the Value column at the end copy and paste this line, ";responseBuffering=adaptive" . save and exit.
next restart sapinst and be happy...