I am run the source.php3 to show the source code, 
but i can not view the actural source code.
  It's error information is follows:

     Source of: /index.php3
--------------------------------------------------------------------------------
    Fatal error: Failed opening required 'index.php3' 
    in C:\Inetpub\wwwroot\php\source.php3 on line 29

  My Web server is IIS 4.0 and 
php3.ini contents is:

[PHP_3]
engine = 1  ; enable PHP 3.0 parser

max_execution_time = 30     ; Maximum execution time of each script, in seconds
memory_limit = 8388608		; Maximum amount of memory a script may consume (8MB)

; error_reporting is a bit-field.  Add each number up to get desired error reporting level
;  1 = Normal errors
;  2 = Normal warnings
;  4 = Parser errors
;  8 = Really picky warnings - ie. using a variable before defining it
error_reporting=7
display_errors=1           ; Print out errors (as a part of the HTML script)
log_errors=0			   ; Log errors into a log file (server-specific log, stderr, or error_log (below))
track_errors=0             ; Store the last error/warning message in $php_errormsg (boolean)
;error_log=filename		; log errors to specified file
;error_log=syslog		; log errors to syslog (Event Log on NT, not valid in Windows 95)

warn_plus_overloading=0		; warn if the + operator is used with strings

magic_quotes_gpc = 1       ; magic quotes for incoming GET/POST/Cookie data
magic_quotes_runtime = 0   ; magic quotes for runtime-generated data, e.g. data from SQL, from exec(), etc.
magic_quotes_sybase = 0    ; Use Sybase-style magic quotes (escape ' with '' instead of \')
track_vars=1               ; enable $PHP_GET_VARS[], $PHP_POST_VARS[] and $PHP_COOKIE_VARS[] arrays
short_open_tag=1           ; allow the <? tag.  otherwise, only <?php is recognized.

precision = 6		; number of decimal digits displayed in floating point numbers
; paths and directories
include_path=C:\Inetpub\wwwroot\php\include;.
doc_root=C:\Inetpub\wwwroot\php;.    ; the root of the php pages, used only if nonempty
user_dir=                     ; the directory under which php opens the script using /~username, used only if nonempty
upload_tmp_dir=C:\winnt\temp  ; temporary directory for HTTP uploaded files
extension_dir=./              ; directory in which the loadable extensions (modules) reside


; file extensions (meaningless in UNIX)
cgi_ext=php3
isapi_ext=php3
nsapi_ext=php3

; automatically add files before or after any PHP 3.0 document
auto_prepend_file=
auto_append_file=


[mail function]
SMTP=localhost                  ;for win32 only
sendmail_from=me@localhost.com  ;for win32 only
sendmail_path=                  ;for unix only

[safemode]
safe_mode=0
safe_mode_exec_dir=

[Debugger]
debugger.host=localhost
debugger.port=7869
debugger.enabled=0

[Logging]
logging=0
log_DBM=0
log_DBM_dir=.
log_SQL=0

[LoadExtensions]
; if you wish to have an extension loaded automaticly, use the
; following syntax:  extension=modulename.extension
; for example, on windows,
; extension=msql.dll

[Highlight]
; Colors for Syntax Highlighting mode.  Anything that's acceptable in <font color=???> would work.
highlight.string	=	#DD0000
highlight.comment	=	#FF8000
highlight.keyword	=	#007700
highlight.bg		=	#FFFFFF
highlight.default	=	#0000BB
highlight.html		=	#000000


[SQL]
sql.safe_mode=0

[MySQL]
mysql.allow_persistent=1 ; allow or prevent persistent link
mysql.max_persistent=-1  ; maximum number of persistent links. -1 means no limit
mysql.max_links=-1       ; maximum number of links (persistent+non persistent).  -1 means no limit

[mSQL]
msql.allow_persistent=1 ; allow or prevent persistent link
msql.max_persistent=-1  ; maximum number of persistent links. -1 means no limit
msql.max_links=-1       ; maximum number of links (persistent+non persistent).  -1 means no limit

[PostgresSQL]
pgsql.allow_persistent=1 ; allow or prevent persistent link
pgsql.max_persistent=-1  ; maximum number of persistent links. -1 means no limit
pgsql.max_links=-1       ; maximum number of links (persistent+non persistent).  -1 means no limit

[Sybase]
sybase.allow_persistent=1 ; allow or prevent persistent link
sybase.max_persistent=-1  ; maximum number of persistent links. -1 means no limit
sybase.max_links=-1       ; maximum number of links (persistent+non persistent).  -1 means no limit
;sybase.interface_file = "/usr/sybase/interfaces"
sybase.min_error_severity=10   ; minimum error severity to display
sybase.min_message_severity=10 ; minimum message severity to display


[Sybase-CT]
sybct.allow_persistent=1 ; allow or prevent persistent link
sybct.max_persistent=-1  ; maximum number of persistent links. -1 means no limit
sybct.max_links=-1       ; maximum number of links (persistent+non persistent).  -1 means no limit
sybct.min_server_severity=10 ; minimum server message severity to display
sybct.min_client_severity=10 ; minimum client message severity to display


[bcmath]
bcmath.scale = 3    ; number of decimal digits for all bcmath functions

[browscap]
;browscap = extra/browscap.ini