weird matlab script error of boolean condition a=(b>0); [error 1048]

[savor]

1: a=(b>0); return a 1048 error, and the result of a is wrong.

2: modify the above equation using a if-then clause

if b>0

a=1;

else

a=0;

end

3:  comment (2) away, (1) still return a 1048 error but the result is right.

i donot know whether you have experienced the same before, but this error is surely annoyed me and cause a night to debug....

the version of matlab and labview is

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MATLAB Version 7.0.4.365 (R14) Service Pack 2
MATLAB License Number: 199834
Operating System: Microsoft Windows XP Version 5.1 (Build 2600: Service Pack 3)
Java VM Version: Java 1.5.0 with Sun Microsystems Inc. Java HotSpot(TM) Client VM
-------------------------------------------------------------------------------------

labview 8.5

here are the pics:

[muks]

Why Does My Script Written in The MathWorks, Inc. MATLAB® Language Syntax Return Error 1048?