Too many arguments

[kommanman]

I keep getting too many arguments when I try to use ISNA. Cell F148 has "#N/A"

=IF(ISBLANK(F14 8)," ",IF(ISBLANK(H1 47),"ok",IF(AND (H148="P/T",H147="F/T"),"Ok",IF(BG1 48>BG147,"OK",I F(BG148=BG147," OK",if(ISNA(f14 8,"")),"BAD"))) ))