Thank you so much for your help. After going through your suggestions, I was able to run the analysis.

Following my previous analysis, I am now running a linear regression analysis on my structural connectivity data and would like to verify my design file. I used the following two contrasts: [0 1 0 0] and [0 -1 0 0] and my design file was structured like the following. 

Example:

[Intercepts, predictor variable, covariate 1, covariate 2]

[1, 45, 0.6, -10.18] 

[1, 67, 7.8, 6.82]

[1, 32, 8.3, -0.18]

In addition, I was wondering whether there is a way to open the results without providing the Node Coordinates (MNI) and Node Labels files. I was able to obtain a significant result, but at the moment I do not have the corresponding Node Coordinates, so I am unable to see which node was found to be significant.

Thank you again for your help and have a great weekend.