IFilter.GetText throwing exception

[babli]

Hi,

I am stuck with this method for more than 2 days...
I am using the GetText method of IFilter class to read text.
The line

IFilterobject.GetText(ref buflength,buffer)

is throwing a COM Exception, dont know why :(

I have set buflength = 512 and buffer is an empty string builder.

Thanks in advance

Babli