I would like to create a database of resting EEG data from healthy neurotypical subjects. To do this, I have written a small program in Matlab for FFT analysis of EEG recordings in *.edf format. I also created a set of recordings in *. Fdt (FieldTrip Data Format). As far as I know, you can use EEGlab to convert the file to edf by first uploading the *.set file and then using Export--->Data to edf file. When you do this, the following error message appears in Matlab.

Warning SOPEN (EDF): A block exceeds 61440 bytes.

Warning SOPEN (EDF-Write): Relative scaling error is 5.880403e-07 (due to roundoff in PhysMax/Min).

Warning SWRITE: 410 NaNs added to complete data block.

As I understand it, these warnings indicate that there are problems with file size, data accuracy, and data padding. Should I ignore these warnings or are they more serious problems? What is the best way to convert ftd files to edf format using Matlab?