JensYes, all actions I did were clean.

I updated my local copy of the svn repository on external drive from the web.
Then, I placed this directory onto computer's hard drive in distinct(new) directory h:\svn_source
(h:\ is a logical hard drive on the host)
Then I consequently built (via standalone C::B 12.11) the following:
h:\svn_source\src\CodeBlocks.cbp (Build->Rebuild)
h:\svn_source\src\ContribPlugins.workspace (Build->Rebuild workspace)
finally run h:\svn_source\src\update.bat
and placed there(output dir) the absent wxmsw28u_gcc_custom.dll
running codeblocks.exe fails with the mentioned violation.
I check it on one of most recent release 91xx.. and on 9000. The result is the same.
I could try to repeat this process again on my earlier good build of rev 8549(I use it as well as 12.11) and see whether something changed concerning my pure Windows system environment. But I am sure it will be built and run with no exception.