User reports "Error #2046", I can't replicate--possible causes?

Question

Hi All,
We've got a Flex 4 app, built in Flash Builder, and we just had a user call in and report that when they click the "Begin" button on the app (the very first user interaction they would have after the app has finished loading), they got "Error message 2046."
That's all the information I have from the user.  I've been doing searching on this and it sounds like Flash runtime error 2046 is an RSL that had an invalid signature.  Here's the official list of runtime errors:
http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/runtimeErrors.html
Now, this is the first user to report this problem, and I've never experienced this myself.  How would I troubleshoot this?  Is there a way to force my browser to try and load all the RSLs for my app?  I'm using Firebug to monitor the requests the browser makes, and I can see it requests my main SWF file, but none of the SWZ files, which I think are the RSLs?  I'm wondering if one of them is "bad" somehow, but I'm not seeing the error because I've got it cached from some other site that used the same RSL?
Also, I'm confused as to why the user wouldn't have gotten this message until they clicked on a button in my app.  Aren't the RSL's loaded as part of the initial app startup?  I would have thought he would have gotten this error during the initial loading of the Flex app, not when he first attempted to click on a button in the app.
I haven't changed with the compiler or RSL settings for my project from the default settings when I created the project.
Thanks for any input/suggestions into what's going on here...
  -Josh

Answer 1

I don't know if I'll have a way to contact this user again, but I'll see if I can find their information.  Thanks for the suggestion on the system clock.
Also, once I followed your instructions on how to delete the RSLs, I can see them requested in Firebug.  I noticed something interesting, however, that I'm hoping someone can help me understand better.
When I change the compiler options from using RSLs to "Merge into code," the total size of my SWF is 852kb.  If I use RSLs, then my SWF is 231kb, and the following additional files are loaded from fpdownload.adobe.com:
1) osmf_flex.4.0.0.13495.swz (96kb)
2) framework_4.0.0.14159.swz (607kb)
3) textLayout_1.0.0.595.swz (129kb)
4) spark_4.0.0.14159.swz (311kb)
5) sparkskins_4.0.0.14159.swz (53kb)
So that's a total of 1196kb in RSLs.  Combine that with my SWF size of 231kb, and you get a total of 1427kb.  That's 575kb (or 67%) more than the 852kb if I simply didn't use RSLs.  So, it looks like if I use RSLs, and the user actually needs to load the RSLs, they will have to load 575kb more than if I simply chose the option "merge into code."
So, I'm guessing that the reason is that when I merge everything into code, it only actually includes the bits that I'm using.  However, when I opt for RSLs, the app must load the entire SWZ file, even if I'm only using a single item in that SWZ file.  Is that right?
As for the reasoning for using loading entire RSLs over merging into your SWF only what you need, I'm guessing it goes like this: though some users might get a slower load experience, most users will already have those RSLs loaded, so they'll only need my smaller (231kb) SWF.
Are there any statistics out there that can give me an idea of just what percentage of users will need to load the RSLs, versus those that will already have them cached locally?
  -Josh