[flex_next] ASDoc tool fails in FB4 with error "Invalid character found"

Steps to reproduce:
1. When the attached config file ( VisFrameworkAsDoc-config.xml )is used to create Documentation using ASDoc tool with existing app migrated to Flex 4 from Flex 3, fails with error [file attached].
2. The same file when used with any sample app created in Flex 4, it works.
3. We need some reasoning/help on debugging the cause of the error in stack trace.

Actual Results:
The ASDoc tool fails with error attached.

Expected Results:
Should work fine.

Workaround (if any):
N/A

Notes:
Same file with existing app in flex 3 used to work fine.

As discussed with Gaurav Jain on Engineering , he asked me to log the bug with Dtrace.all=true in jvm.config and attach the stack trace. [unfortunately it does not give us any more info ]

We need to either find the answers :

• Either a way to get more error logging ,
• or the cause of this error.

Customer has FB4 in Eclipse , so we have changed the flag in Eclipse's jvm.config.