Error Debugging the project

[AbidaNidhal]

Hi, I'm not sure if I'm doing something wrong but I keep getting these 2 errors when compiling the project

The 1st:
Severity Code Description Project File Line Suppression State
Error LNK1104 cannot open file 'Debug\four_d_association.lib' mocap C:\4d_association-linux\build\vs2019-x64\four_d_association\LINK 1

The 2nd:
Severity Code Description Project File Line Suppression State
Error C2446 '==': no conversion from 'Scalar' to 'Eigen::ArrayWrapper' four_d_association C:\4d_association-linux\include\Eigen\src\Cholesky\LDLT.h 373

this is the line causing the probelm and I don't have enough knowledge to change it.
ret = ret && (mat.col(j).tail(size-j-1).array()==Scalar(0)).all();