% [num,txt] = xlsread('C:\Program Files\MATLAB\R2012a\StockSymbols.xls')
% or another alternive: Browse file location

[f, p] = uigetfile({'*.xls';'*.xlsx'},'Pick StockSymbols file');
filename=fullfile(p,f);
[num,txt] = xlsread(filename);

% Get stocks
DATE = txt(2:end,1); % Date begins from second row

% Sort data in case dates are not in chronological order
[DATE_num,sortIndex] = sort(datenum(DATE,'mm/dd/yy')); % no hour,minute and second in your date data

BA = num(sortIndex,1);
BAC = num(sortIndex,2);
CAT = num(sortIndex,3);
CSCO = num(sortIndex,4);
DIS = num(sortIndex,5);
GE = num(sortIndex,6);
HD = num(sortIndex,7);
IBM = num(sortIndex,8);
JPM = num(sortIndex,9);
KFT = num(sortIndex,10);
KO = num(sortIndex,11);
MMM = num(sortIndex,12);
MSFT = num(sortIndex,13);
PFE = num(sortIndex,14);
PG = num(sortIndex,15);
T = num(sortIndex,16);
VZ = num(sortIndex,17);
XOM = num(sortIndex,18);

% DATE_num = datenum(DATE,'dd/mm/yy'); % no hour,minute and second in your date data
hf=figure('Units','normalized','Position',[0.05 0.05 0.9 0.7]);
plot ( DATE_num , BA , 'r'), hold on, grid on % hold if you want to plot on the same figure, add grid
title('Stock Symbols');
xlabel('Dates');
ylabel('Stock Symbols ($)');

plot ( DATE_num , BAC, 'b')
plot ( DATE_num , CAT ,'k')
plot ( DATE_num , CSCO, 'g')
plot ( DATE_num , DIS, 'm')
plot ( DATE_num , GE, 'c')

% Add legend if wanted
legend('BA','BAC','CAT','CSCO','DIS','GE','Location','Best')

% Set axes labels
 mindate=min(DATE_num);
 maxdate=max(DATE_num);
 ha=get(hf,'CurrentAxes');
 set(ha,'XTickLabelMode','manual','XTickMode','manual','XLimMode','manual',. ..
    'XLim',[mindate-15 maxdate+15],'XTick',linspace(mindate,maxdate,10));
% % %  xticklabels=datestr(get(ha,'XTick'),24); % Will be used to label the X axis, format is dd/mm/yyyy
% % %  set(ha,'XTickLabel',xticklabels);
% % %  
dateaxis('x',1);

All it does not is open a chart, but nothing gets plotted.  I don't get any errors.

Below is a sample file to download and put in the Matlab folder (so you don't have to spend a lot of time creating your another Excel file).
http://www.mediafire.com/view/?gjd29zoo7p4c8kw

You need to change your initial date/data processing to reflect your actual data file.

Phil.

I executed

[num,txt] = xlsread('StockSymbols.xls');

and noticed that txt only had one row in it => no dates.
Then I opened the Excel file (in Excel not MATLAB) and confirmed that there are no dates represented as text.

Phil.