documentclass{article}

usepackage{datatool}
usepackage{colortbl}

begin{filecontents*}{bogus.csv}
FirstName,Surname,StudentNo,Score
John,"Smith, Jr",102689,68
Jane,Brown,102647,75
Andy,Brown,103569,42
Z"oe,Adams,105987,52
Clare,Verdon,104356,45
John,"Smith, Jr",102683,68
Roger,Brady,106872,58
Clare,Verdon,104356,45
end{filecontents*}

begin{document}

DTLloaddb{dat}{bogus.csv}
begin{table}[htbp]
caption{Conditionally colored rows}label{tab:colored_row}
centering
begin{tabular}{llc}
bfseries First Name &
bfseries Surname &
bfseries Grade (%)%
DTLforeach{dat}
           {firstname=FirstName, surname=Surname,score=Score} %
           {\ % skip line
           %DTLifoddrow{ rowcolor{blue} }{ rowcolor{green} } % stripy conditional. works fine.
           DTLifnumlt{score}{60}{rowcolors{geen}}{rowcolors{blue}} % my conditional. no go.
           firstname & surname & score} %
end{tabular}
end{table}

end{document}