error when I try the example

[lihuishanghaitech]

when I try to install the eSynth, it has some warning:
Main.cpp: In function ‘void readMoleculeFile(const char*)’:
Main.cpp:207:14: warning: unused variable ‘notAtEnd’ [-Wunused-variable]
bool notAtEnd = obConversion.ReadString(mol, prefix);
^
Main.cpp: In function ‘int main(int, char**)’:
Main.cpp:351:29: warning: variable ‘graph’ set but not used [-Wunused-but-set-variable]
MoleculeHashHypergraph* graph = 0;
^
OBWriter.cpp: In member function ‘void OBWriter::IndicateSMIwritingComplete() const’:
OBWriter.cpp:398:24: warning: ignoring return value of ‘int system(const char*)’, declared with attribute warn_unused_result [-Wunused-result]
system(zip.c_str());

And after it success create the file eSynth, when I try to try the example, it make mistake:

^
./esynth -nopen -serial -smi-only -prob-level 2 l-test-linker1.sdf l-test-linker2.sdf r-test-rigid1.sdf r-test-rigid2.sdf
Serial execution.
Probability Filtration Level: 2
./esynth: symbol lookup error: ./esynth: undefined symbol: _ZN9OpenBabel12OBConversion11SetInFormatEPKcb

Looking forward to your reply!