It's not the file name, or even the operating system, it's the size of the file that's the problem. The formatting of the pendrive is probably FAT32 which as per Wikipedia
http://en.wikipedia.org/wiki/File_Allocation_Table#FAT32 has a maximum file size of 4 GiB minus 1 byte or 4,294,967,295 (2^32 − 1) bytes. FAT32 is the default filesystem for USB flash drives. You can confirm this from a terminal window with
sudo fdisk -l /dev/sdX (the value of 'X' is probably b, as the USB flash drive probably is the second drive in your system).
Now, if you just want to move the ISO using the flash drive to carry it, you can use http://sourceforge.net/projects/p7zip/ , http://linux.die.net/man/1/7z , or other archival utilities to break the file into two pieces, and then carry it to your destination. If so, just use 'store' mode compression, that is to say, no compression, for the fastest operation. Or, you could reformat the flash drive for http://en.wikipedia.org/wiki/Ext2 or http://en.wikipedia.org/wiki/NTFS which have a file size limit of 16 TiB-1, orders of magnitude larger.
But, perhaps you wish to make the flashdrive bootable with that ISO? If so, then use unetbootin (installed with
apt-get install -y unetbootin if your system does not have it) to create a bootable flashdrive with the contents of the ISO.