All we've really got to go on is the message returned from PclZip:
0002.628 (0) Closing the zip file returned an error (PCLZIP_ERR_READ_OPEN_FAIL (-2) : Unable to open temporary file 'pclzip-5440288bbd549.tmp' in binary write mode).
So, it can't open a temporary file. That might be because of permissions; it might be lack of disk space; it might be some other weird server quirk that I can't think of. I think the best thing at this point would be to ask the web hosting company to take a look at the error message, and ask them for input.
David