the programm ignores my 'if' condition

hi everyone.

I can't understand why the inner 'if' loop here doesn't work. I get 'Array indices must be positive integers or logical values' message, although it's supposed to act only if the index is >0:

for p=1;
    for o=[0:17449];
        if ~isempty(sequences{1}{20+30*(o)}(human_PRE_perm_or_not{o+1,p}{:}-5))
            if (human_PRE_perm_or_not{o+1,p}{:}-5)>0
                base_minus5_human{o+1, p}=sequences{1}{20+30*(o)}(human_PRE_perm_or_not{o+1,p}{:}-5);
            end
        end
    end
end

thanks in advance.

[chaim giladi]

oh, I got it...

of course :)