Error while exporting ALV to excel?

Hi Gurus,

I'm stuck at a weird error.

For a particular Z report, when I'm exporting ALV report through Menu List->Export->Spreadsheet, and then selecting "Star Office 8 Calc / OpenOffice.orf 2.0 Calc", what is happening is that, sometimes the ALV downloads, sometimes it gives a dump (INTERNAL_ERROR, i've attached the short dump) and sometimes it gives an error while opening the downloaded excel.

This error comes in OpenOffice, but I'm also unable to open the file in MS Excel.

I'm using  REUSE_ALV_FIELDCATALOG_MERGE for preparing fieldcatalog. Earlier the fieldcatalog was prepared manually, but still the error was coming.

Any suggestions please?

Thanks!

Bhuvan Paliwal