I have a dataset with 20 features and 102 observation. When I use Amelia I got this error error: inv_sympd(): matrix appears to be singular. The resulting variance matrix was not invertible.   Please check your data for highly collinear variables. Then I used spearman correlation to get rid of highly collinear features:

I found the elements that have value >= 0.9 in my cor matrix. I removed corresponding features from dataset. There were some elements with value NA  in cor matrix, I don't know what they mean but I removed them as well. Then, I only got 12 features which are correlated less than 0.9. However I still get this error: 

How can I correct this error? 

Thank you!