I'm calling mc_issue_attachment_get with a correct username/password/attachment id.

The error response is:

<SOAP-ENV:Envelope SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/">

<SOAP-ENV:Body>

<SOAP-ENV:Fault>

<faultcode xsi:type="xsd:string">Server</faultcode>

<faultactor xsi:type="xsd:string"/>

<faultstring xsi:type="xsd:string"><![CDATA[Error Type: SYSTEM NOTICE,

Error Description:

Undefined index:  project_id,

Stack Trace:

mc_issue_attachment_api.php L24 mci_file_get(<integer>2, <string>'bug', <string>'1')

UnknownFile L? mc_issue_attachment_get(<string>'administrator', <string>'root', <integer>2)

nusoap.php L3997 call_user_func_array(<string>'mc_issue_attachment_get', <Array> { [0] => 'administrator', [1] => 'root', [2] => 2 })

nusoap.php L3686 invoke_method()

mantisconnect.php L1391 service(<string>'<soapenv:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:man="http://futureware.biz/mantisconnect">

<soapenv:Header/>

<soapenv:Body>

<man:mc_issue_attachment_get soapenv:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">

<username xsi:type="xsd:string">xxx</username>

<password xsi:type="xsd:string">xxx</password>

<issue_attachment_id xsi:type="xsd:integer">2</issue_attachment_id>

</man:mc_issue_attachment_get>

</soapenv:Body>

</soapenv:Envelope>')]]></faultstring>

<detail xsi:type="xsd:string"/>

</SOAP-ENV:Fault>

</SOAP-ENV:Body>

</SOAP-ENV:Envelope>

It seems to me that mci_file_get unconditionally reads $row['project_id'] at line 163, but that field is not present in mantis_bug_file_table:

mysql> describe mantis_bug_file_table;

+-------------+------------------+------+-----+---------+----------------+

| Field       | Type             | Null | Key | Default | Extra          |

+-------------+------------------+------+-----+---------+----------------+

| id          | int(10) unsigned | NO   | PRI | NULL    | auto_increment |

| bug_id      | int(10) unsigned | NO   | MUL | 0       |                |

| title       | varchar(250)     | NO   |     |         |                |

| description | varchar(250)     | NO   |     |         |                |

| diskfile    | varchar(250)     | NO   | MUL |         |                |

| filename    | varchar(250)     | NO   |     |         |                |

| folder      | varchar(250)     | NO   |     |         |                |

| filesize    | int(11)          | NO   |     | 0       |                |

| file_type   | varchar(250)     | NO   |     |         |                |

| content     | longblob         | NO   |     | NULL    |                |

| date_added  | int(10) unsigned | NO   |     | 1       |                |

| user_id     | int(10) unsigned | NO   |     | 0       |                |

+-------------+------------------+------+-----+---------+----------------+

12 rows in set (0.00 sec)

Please consider fixing this for the next 1.2 RC or release, as it's a showstopper for most consumers of the SOAP API.