It looks like your data does not have a header (where the first error comes from). This can be inspected to confirm (no need to guess) by clicking on the “eye” icon to view the first lines of one (or all) of the count datasets. Galaxy will create headers if none are included already in the inputs.
This sometimes comes up (second error) when the wrong input is selected by mistake. Example: summary/report data was input instead of count data.
If you would like to compare to sample data/workflows, please see the RNA-seq tutorials. “Reference-based RNA-Seq data analysis” includes DESeq2.