Adobe FLEX 2-PROGRAMMING ACTIONSCRIPT 3.0 Manual page 276

Class name
MemoryError
ScriptTimeoutError
StackOverflowError The StackOverflowError
276 Handling Errors
Description
A MemoryError exception is
thrown when a memory
allocation request fails.
A ScriptTimeoutError exception
is thrown when a script timeout
interval of 15 seconds is reached.
By catching a
ScriptTimeoutError exception,
you can handle the script timeout
more gracefully. If there is no
exception handler, the uncaught
exception handler will display a
dialog box with an error
message.
exception is thrown when the
stack available to the script has
been exhausted.
Notes
By default, ActionScript Virtual
Machine 2 does not impose a limit
on how much memory an
ActionScript program may allocate.
On a desktop PC, memory
allocation failures are infrequent.
You see an error thrown when the
system is unable to allocate the
memory required for an operation.
So, on a desktop PC, this exception
is rare unless an allocation request
is extremely large; for example, a
request for 3 billion bytes is
impossible because a 32-bit
Windows program can access only
2 GB of address space.
To prevent a malicious developer
from catching the exception and
staying in an infinite loop, only the
first ScriptTimeoutError exception
thrown in the course of a particular
script can be caught. A subsequent
ScriptTimeoutError exception
cannot be caught by your code and
will immediately go to the uncaught
exception handler.
A StackOverflowError exception
might indicate that infinite recursion
has occurred.