Error: Object returned error code: 0x800A03EC when using actxserver, get command.

I am trying to update the excel file using actxserver. I am trying to write more than 256 columns in the excel file. the format of the excel file is xlsx. Following is the code snitted which I am using to write: lastCol = 10; for i = 1:(720/4) lastCol = lastCol + 1; alphabet = num2alp(lastCol); write_alphabet_from = alphabet; columntill = lastCol + 3; alphabet = num2alp(columntill); write_alphabet_till = alphabet; lastCol = columntill; range=[write_alphabet_from num2str(1) ':' write_alphabet_till num2str(1)]; exlSheet1.Activate; exlSheet1 = exlSheet1.get('Range',range); exlSheet1.MergeCells = 1; val = strcat('Columan Title ',num2str(i)); exlSheet1.Value = val; end note: 1) num2alp is a function which returns me a the alphabetical name of the column in excel which I am later using to write the data. 2) 720/4 is only to ensure that I have (720/4) merged cells which I can use as header. But later write operation will be done in all 720 columns in the excel. 3) I am able to update data for 1st 10 columns, hence variable lastCol is set to 10 at the beginning of the loop.

I am getting error with "exlSheet1 = exlSheet1.get('Range',range)" when "i" reaches 89.

Any help to resolve it is very much appreciated !!

Cheers !!