I have been looking so much for this error in Coldfusion MXÂ but could not find any solution to my problem. null null is a very vague exception error which gets thrown once in a while. Below are the steps I did to troubleshoot and one of them did the solved the problem.
 1) Apply this hot fix from Adobe.
2) Increase the JVM Heap Size. (I increased it  from 512 to 800)
3) Make sure your SELECT query does not pass any corrupt data. It might also be the very cause to  throw the exception error.Turning off query caching signifigantly increased the number of errors, so it seems to be something in the JDBC drivers.
4) Check to see if you have methods that accept parameters passed by reference(like getimagesize()) . Make sure you use right script language for example getimagesize uses VBSCRIPT not JSCRIPT. ( For me this was the case. I removed this method and it stopped the error completely).
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the null null fix is here
http://kb.adobe.com/selfservice/viewContent.do?externalId=b3c51ba1&sliceId=1