hardcore gdc problems

[Downs]

I've been running into problems with gdc for a while now (.21-.23, mingw32, 3.4.5 and 4.1.2), specifically crashes in odd places (language constructs).
It only seems to happen when I run many threads in parallel; are there any known issues with that?
Here's a log of a debugging session I made recently, after rebuilding Phobos without -O2 (Line space added):

D:\code\d\yawr>gdb bin\dbg\yawr.exe
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This GDB was configured as "i686-pc-mingw32"...


(gdb) r
Starting program: D:\code\d\yawr/bin\dbg\yawr.exe

Program received signal SIGSEGV, Segmentation fault.
[Switching to thread 2448.0xb18]
0x022cfea9 in ?? ()


(gdb) bt
#0  0x022cfea9 in ?? ()
#1  0x00421525 in _d_throw (obj=@0x1e17770)
     at ../../../gcc-4.1.2/libphobos/gcc/deh.d:99
#2  0x0042df41 in _D3std6socket15InternetAddress5_ctorMFAatZC3std6socket15Intern
etAddress (this=@0x1ea51a0, addr=
       {length = 18, ptr = 0x1bf4a67 "talismenseries.com/"}, port=80)
     at ../../../gcc-4.1.2/libphobos/std/socket.d:676
#3  0x0040337b in _D4main11do_DownloadFAaZAa (param=
       {length = 26, ptr = 0x1bf4a60 "http://talismenseries.com/"}) at main.d:67
#4  0x0040aed7 in _D4main8downloadFAaDFfZvZAa13__dgliteral26MFAaZAa (c=
       {length = 26, ptr = 0x1bf4a60 "http://talismenseries.com/"})
     at main.d:830
#5  0x00410692 in _D5tools6buffer17__T6bufferTAaTAaZ6buffer3getMFAaZAa13__dglite
ral73MFZb () at tools/buffer.d:37
#6  0x00547cc2 in _D5tools6buffer17__T6bufferTAaTAaZ6buffer3getMFAaZAa (
     this=@0x1e73c80, idx=
       {length = 26, ptr = 0x1bf4a60 "http://talismenseries.com/"})
     at tools/buffer.d:28
#7  0x0040ae84 in _D4main8downloadFAaDFfZvZAa (url=
       {length = 26, ptr = 0x1bf4a60 "http://talismenseries.com/"}, progress=
       {object = 0x52cfe8c, func = 0x411387 <_D4main17__T6fhtagnVb0Vb0Z6fhtagn6up
dateMFDFZvZv13__dgliteral87MFfZv>}) at main.d:834
#8  0x0053dec1 in _D4main17__T6fhtagnVb0Vb0Z6fhtagn6updateMFDFZvZv (
---Type <return> to continue, or q <return> to quit---
     this=@0x1da1880, redraw=
       {object = 0x1df2a80, func = 0x40b912 <_D4main14user_interface7refreshMFZv>
}) at main.d:535
#9  0x00538579 in _D3std4bind101__T9BoundFuncTDFDFZvZvS41_D3std4bind9NullAliasS3
std4bind9EmptySlotTS3std4bind15__T5TupleTDFZvZ5TupleZ9BoundFunc16__T10MBoundFunc
Z4funcMFZv (this=@0x1c48d00)
     at c:/mingw/bin/../lib/gcc/mingw32/4.1.2/../../../../include/d/4.1.2/std/bin
d.d:527
#10 0x0041001d in _D4main10poolthread3runMFZi (this=@0x1de7080) at main.d:1256
#11 0x0043a75f in _D3std6thread6Thread11threadstartWPvZk at 4 (p=0x1de7080)
     at ../../../gcc-4.1.2/libphobos/std/thread.d:412
#12 0x77c3a3b0 in _libws2_32_a_iname ()
#13 0x7c80b683 in _libws2_32_a_iname ()


(gdb) f 1
#1  0x00421525 in _d_throw (obj=@0x1e17770)
     at ../../../gcc-4.1.2/libphobos/gcc/deh.d:99
99              _Unwind_SjLj_RaiseException (&exc.unwindHeader);


(gdb) i loc
exc = (OurUnwindException *) 0x1e16800


(gdb) p *exc
$1 = {handlerSwitchValue = 0, actionRecord = 0x0, languageSpecificData = 0x0,
   catchTemp = 0, landingPad = 0, obj = @0x1e17770, unwindHeader = {
     exception_class = 26844869579591239,
     exception_cleanup = 0x421495 <_gdc_cleanupException>, private_1 = 0,
     private_2 = 0}}
(gdb)

Any idea how to proceed from here? This error has me totally stumped. (if anybody wants to read the source, it's in yawr.svn.sourceforge.net/viewvc/yawr/ )
Could this be related to stack corruption/buffer overflows? The backtrace looks intact but I used to have issues with stack corruption
in connection with SDL .. I believed I had fixed these, but it is possible that errors remain. Ideas?
  -- slightly despairing, downs