Auotcad export/import to/from QCAD3- problem

[QTrain]

Hello together,
i have this configuration.
qcad 3.11 on Linux openSUSE 13.2 (Harlequin) (x86_64) 64-Bit /AMD FX(tm)-8320 Eight-Core Processor × 8
The System is very stable/no problems.
The Problem:
1. I get from outside an autocad .dwg (Autodesk Building Design Suite Standard 2013 on a Windows-machine)
2. I make with qcad any changes
3. store in a .dwg-File with new name
4. send it with email outside to a autocad-User (s.1)
hint: on qcad side: no problems to reload/store the file
5. the autocad user want to open the .dwg and gets in 90% of cases error: unhandled Access Violation Reading (s. file #1)
6. qcad: shows many text with add. letters (s. file #1: Text "Flur"-"66,24 m[u][b]\U+00b2[/b][/u]" \U+00bs is wrong-> m²
I made some test with other dwg-formats 2007, ... the same problems

I attach
a) an original autocad file (s. file#2)
b) the qcad file with changes (s. file #3) which faile on windows-machine in autocad

Please see this information and help me to solve the problem or to have a workaround.

[andrew]

5. the autocad user want to open the .dwg and gets in 90% of cases error: unhandled Access Violation Reading (s. file #1)

This is unfortunately a tough one which likely cannot be fixed from our side. The QCAD file seems to load fine with autocad360.com and other CAD software.

6. qcad: shows many text with add. letters (s. file #1: Text "Flur"-"66,24 m\U+00b2" \U+00bs is wrong-> m²

I cannot reproduce this here. Texts are shown correctly with "m²" in QCAD.