PDF files truncated when using Firefox

[Roger_70]

Dear all,
a customer has experienced some problems when downloading PDF files using Firefox.
He has tried accessing the remote application, to download PDF files, both via iChain and without passing through the iChain and, in the first case, the downloaded PDF files have been truncated, preventing Adobe to open them.
The http response header has in both cases the same, correct content-length (11734), that of the complete file (in what follows, I've replaced the actual URL and Username used with <URL> and <username>, respectively).
Can you please help me in understanding how to solve this issue?
Thank you in advance
Roger_70

With iChain:
http:// <URL>/CRG/run_report
POST /CRG/run_report HTTP/1.1
Host: <URL>
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.8.1.14) Gecko/20080404
Firefox/2.0.0.14
Accept:
text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
Accept-Language: en-gb,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 300
Connection: keep-alive
Referer:
http://<URL>/CRG/edit_report?db=COSY_2%5ECOSY_2APP&table=ACMS_ACTIV ITY
Cookie: TGS_username=<username>;
DAM_targeturl=http://<URL>/CRG/edit_report?db=COSY_2%5ECOSY_2APP&table=ACMS_A
CTIVITY; IPCZQX01575d27fd=0000d5002cacde332a0f11ea; ZNPCQ002-crgacc=V001f8abd68f;
ticket=>iRT.H)2dUCtXo[2]V?<Spx^lK`pKDdLRn/SEi*!bKC!/%
Content-Type: application/x-www-form-urlencoded
Content-Length: 449
ReportName=CRG&ReportPath=FRS%2FCRG&vers=1.1&edit= 0&view=&table=ACMS_ACTIVITY&db=C
OSY_2%5ECOSY_2APP&sql_clause=&qu_form_url=&desc=&r ept=Table%3A+ACMS_ACTIVITY%2C+C
riteria%3A%5E%3CQUERY%3E&rwid=90&ncol=4&sepa=1&lin s=&format=pdf&limit=0&head=ACTIVITY_
CODE%7CACTIVITY_NAME%7C%7C&widt=%7C%7C%7C&hide=0&u ser=&field=V%3AACTIVITY_COD
E%7C1a%7C%7C0%7C0%7C0&field=V%3AACTIVITY_NAME%7C2a %7C%7C0%7C0%7C0&qrows=1&
qopen=0&qfield=&qopera=&qvalue=&qclose=0&qlogic=0
HTTP/1.x 200 OK
Date: Thu, 29 May 2008 13:02:22 GMT
Server: Apache/1.3.27 (Unix)
content-disposition: attachment; filename="COSY-2.pdf"
Content-Type: application/pdf
Content-Length: 11734
Via: 1.1 ICS_SERVER (iChain 2.3.278)

Without iChain:
http://<URL>/CRG/run_report
POST /CRG/run_report HTTP/1.1
Host: <URL>
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.8.1.14) Gecko/20080404
Firefox/2.0.0.14
Accept:
text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
Accept-Language: en-gb,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 300
Connection: keep-alive
Referer: http:// <URL>/CRG/edit_report?db=COSY_2%5ECOSY_2APP&table=ACMS_ACTIV ITY
Cookie: TGS_username=<Username>;
DAM_targeturl=http:// <URL>/CRG/edit_report?db=COSY_2%5ECOSY_2APP&table=ACMS_A
CTIVITY; IPCZQX01575d27fd=0000d5002cacde332a0f11ea;
ticket=>iRT.H)2dUCtXo[2]V?<Spx^lK`pKDdLRn/SEi*!bKC!/%
Content-Type: application/x-www-form-urlencoded
Content-Length: 449
ReportName=CRG&ReportPath=FRS%2FCRG&vers=1.1&edit= 0&view=&table=ACMS_ACTIVITY&db=C
OSY_2%5ECOSY_2APP&sql_clause=&qu_form_url=&desc=&r ept=Table%3A+ACMS_ACTIVITY%2C+C
riteria%3A%5E%3CQUERY%3E&rwid=90&ncol=4&sepa=1&lin s=&format=pdf&limit=0&head=ACTIVITY_
CODE%7CACTIVITY_NAME%7C%7C&widt=%7C%7C%7C&hide=0&u ser=&field=V%3AACTIVITY_COD
E%7C1a%7C%7C0%7C0%7C0&field=V%3AACTIVITY_NAME%7C2a %7C%7C0%7C0%7C0&qrows=1&
qopen=0&qfield=&qopera=&qvalue=&qclose=0&qlogic=0
HTTP/1.x 200 OK
Date: Thu, 29 May 2008 13:03:44 GMT
Server: Apache/1.3.27 (Unix)
content-disposition: attachment; filename="COSY-2.pdf"
Content-Length: 11734
Content-Type: application/pdf
X-Cache: MISS from <URL>
Keep-Alive: timeout=15, max=99
Connection: Keep-Alive