Question on the PEAR package Excel_writer

Hi, I have created a program that uses the PEAR package Excel writer. Its functionality is to write out some header titles, etc. then extract and write data from a MySQL database. In addition I insert a number of bitmap images (24bit). The program runs fine on my own server (Windows Apache PHP 4.22). However, when I upload this to my host server (Linix, Apache, PHP 4.3.11) the spreadsheet is not generated, but the following error message is displayed: xxx.bmp doesn't appear to be a valid bitmap image. When removing all the insert_bitmap statements, the program runs fine on the host server. BTW, the images are 24bit bmp files. I have added the MIME type bmp thru the cPanel of my host company. I am able to view the same .bmp images I am using in the spreadsheet in a simple .html file. I have posted this question on various forums, but have not received an answer to my question that will make the program work. I would be grateful for any help offered. Thanks in advance. Regards Bea