Neighbor Joining Tree

[mira1]

I made an IBS distance matrix using PLINK and would like to use this matrix to build a neighbor joining tree in 'Neighbor' of the PHYLIP package. When I read in the resulting matrix from PLINK in Neighbor and try to run then I get the following message:

 

'ERROR: diagonal element of row 1 of distance matrix is not zero'

 

What goes wrong? Can I not directly use the PLINK output?

How can I solve this problem?

 

I'm not really familiar with these methods so I hope someone could help.