[Swift-user] execution error

[Sheri Mickelson]

Hi,

I'm seeing this error message when I'm trying to execute a Swift script:

Execution failed:
	First operand is null

Here's the information from the log file:

2012-03-16 11:54:58,725-0600 DEBUG VDL2ExecutionContext First operand  
is null
First operand is null

	at org.griphyn.vdl.karajan.lib.Operators.vdlop_eq(Operators.java:181)
	at sun.reflect.GeneratedMethodAccessor3.invoke(Unknown Source)
	at  
sun 
.reflect 
.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java: 
43)
	at java.lang.reflect.Method.invoke(Method.java:616)
	at  
org 
.globus 
.cog 
.karajan 
.workflow 
.nodes.functions.FunctionsCollection.function(FunctionsCollection.java: 
82)
	at  
org 
.globus 
.cog 
.karajan 
.workflow.nodes.functions.AbstractFunction.post(AbstractFunction.java: 
27)
	at  
org 
.globus 
.cog 
.karajan 
.workflow 
.nodes 
.AbstractSequentialWithArguments 
.futureModified(AbstractSequentialWithArguments.java:208)
	at org.griphyn.vdl.karajan.DSHandleFutureWrapper 
$1.run(DSHandleFutureWrapper.java:63)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java: 
471)
	at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
	at java.util.concurrent.FutureTask.run(FutureTask.java:166)
	at  
java 
.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java: 
1110)
	at java.util.concurrent.ThreadPoolExecutor 
$Worker.run(ThreadPoolExecutor.java:603)
	at java.lang.Thread.run(Thread.java:636)


I'm having trouble finding the bug in my Swift code.  What type of  
error usually causes this message?

Thanks, Sheri