Hi,
Are you using windows ?
if yes,
please change this line :
Qt Code:
  1. LIBS+= -L"../MyQTLib-build-desktop-Qt_4_8_0_for_Desktop_-_MinGW__Qt_SDK__Debug/debug/libMyQTLib.a"
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to
Qt Code:
  1. LIBS+= -L"../MyQTLib-build-desktop-Qt_4_8_0_for_Desktop_-_MinGW__Qt_SDK__Debug/debug/" -lMyQTLib
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Best regards,

Toto