Visual studio can't remove dll?

Question

Visual Basic

I add the following commands to the Post Build Event:

@echo Start
@echo --------------------------------------
@echo Delete folders
IF EXIST "$(TargetDir)Отчеты" RD /S /Q "$(TargetDir)Отчеты"
IF EXIST "$(TargetDir)de" RD /S /Q "$(TargetDir)de"
IF EXIST "$(TargetDir)es" RD /S /Q "$(TargetDir)es"
IF EXIST "$(TargetDir)ja" RD /S /Q "$(TargetDir)ja"
IF EXIST "$(TargetDir)lib" RD /S /Q "$(TargetDir)lib"
IF EXIST "$(TargetDir)dbg" RD /S /Q "$(TargetDir)dbg"
@echo
@echo Copy pdb
xcopy  /Y "$(TargetDir)*.pdb" "$(TargetDir)dbg\*.pdb"
@echo Delete pdb
del /Q "$(TargetDir)*.pdb"
@echo
@echo Copy dll
xcopy  /Y "$(TargetDir)*.dll" "$(TargetDir)lib\*.dll" 
@echo Delete dll
del /F /Q "$(TargetDir)*.dll"

all dll's and pdb's are copied to their respective folders, but when the pdb files are deleted, the dll's are not.