[Wien] x symmetry -up ERROR: negative position in rstruc

[Dat Do]

Dear wien users,
I'm trying to generate struct file for defect by doing the following
procedure:
1. start with primitive unit cell
2. run supercell command to generate 2x2x2 F supercell
3. split two atom (I would like to have two defects)
4. run x sgroup and copy the case.struct_sgroup to case.struct
3. run initiate as usual.
4. Error occurred at the command: x symetry -u with the message: "ERRO:
negative position in rstruc. Please report"

Do you have any idea why that happened and how to avoid it.
Thanks in advanced,
ps: My system info is:
1. Wien2k 2011.1(Apr 2011) serial version.
2. Machine: HP ProLiant DL160 G6 with 8 Intel Xeon (Nehalem) cores and 24GB
of memory

I attach here the struct file.
------
Dat Thanh Do
Graduate student,
Physics and Astronomy Department, Michigan State University,
East Lansing, Michigan, 48824, US.
Email: dodat at msu.edu
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