I can't help you with this, I'd suggest that you send a description of the problem together with the relevant part of your thebat_Exceptions.log and ex_log.txt files to the Ritlabs.
You can open that site by selecting in The Bat!:
Help -> Feedbak -> Bug Report

I guess that's something for the developers.

However, What you want to achieve can't be done the way you're doing it.
You can't create a new message in a defined folder. All new mesages are created per default in the Outbox.
Furthermore I don't understand what message ytou want to move  to DEF, the received message or the newly created one, in the latter case that won't work either as the filter will continue to process the received message.

The way I'd handle this would be to export the message to a text file (called something fancy like export.msg) and use a template that starts with the the macro %Headers followed by an empty line. Next you can place your regexp.
As next action in your filter you place an external command that imports the message you just created. The command to do that would look like this:
"C:\Program Files\The Bat!\thebat.exe"  /ImportU=accountname;F=foldername;IN=Filename.
Account, folder or filenames that include spaces ought to be included between quotation marks " ".
Yes, it is possible to start TB as an external application from a filter line. The command issued via the command line will be executed even though there won't be running a second instance of The bat!

It's even possible that this other filter won't cause an AV. That your filter causes an AV still is a bug though and needs to be reported.

One final note.
You mentioned that you enabled 'continue processing with other filters' for all of your filters.
The way the sorting office is designed shouldn't make that necessary. To the contrary, I'd say. I haven't enabled that option for any filter at all.

When a filter condition is compared to a message there are two possibilities, you've got a match or you don't.
In case there's a match the filter actions will be executed and the message won't be processed by other filters.
In case there's no match, the message will be processed by the next filter and the next and the next.... until you've run out of filters or you've got a match.
To give an example. I do a lot of filtering on address book groups and my brother is in three groups I use for filtering. my first address book group filter checks whether the sender is in the group relatives and moves the message to the corresponding folder. Now it stops processing the message as it has a match. With the 'continue...' option checked for all filters it ould next move the message to the local users folder and to a club folder and it would be left at the folder that I deem least important (as the filter is placed at the bottom of the sorting office)
So without the 'continue processing...' option enabled you need to place the most important filter on top, whereas you need to place the most important at the bottom when you enable the option, but in that case the message might be processed by several filters each filter taking a tiny bit of processing time and thus burden your computer more.
I don't know how many filters you've got, but I've got over a hundred incoming filters and I wouldn't care for all messages to be matched against all of them. The filters that handle most messages are located at the top of the sorting office (as far as a logical sorting of the conditions is allowing that)

Well, that was rather long for a final note, but I guess that shows how importnt I think it is.

Well, I didn't know about the 'formatted message' option, that wasn't possible in the past and I tend to rely on my memory when commenting on these things. What you don't use you don't notice.

I noticed that you use these macros to rebuild the headers of the message:
%From="%OFromName <%OFromAddr>"
%To="%OToName <%OToAddr>"
%ReplyTo="%OReplyAddr"
%Subj="%OSubj"
Is there any reason why you don't uncheck the option
'Do not preserve header of the original message'? That would take away the need to recreate those headers.

About the 'continue processing...' option. It's not only the speed of processing but it makes it more difficult to hunt any bugs in your sorting system as any message gets checked against every filter.
You had several options to take care of this and in my opinion you picked the very worst.
1 - Enable 'continue processing..' for all filters, you picked that one.
2 - Place the 'create formatted message' filter immediately above the colouring filter and only enable 'continue processing...' for the 'create formatted message' filter.
3 - Place the 'create formatted message' filter somewhere above the colouring and add a colouring action to the 'create formatted message' filter and don't use 'continue processing...' anywhere.
4 - Set the 'create formatted message' filter as subfilter of the colouring filter and don't use 'continue processing...' anywhere.
Personally I'd prefer #3 or #4 with a slight preference for the latter.