Dear Basis,
Disable the fullyMaterializeLobData property by using the parameter fullyMaterializeLobData=false
Default value is true so it is trying to load the whole data at once, if you set the property to false then it will fetch the LOB data in small chunk.
Error during bootstrap:  Attempt to fully ... | SCN
You can also increase the value of heap memory of java system to export the content.
With Regards
Ashutosh Chaturvedi