This is all i have in the manual...

SQL30020N Execution failed because of a Distributed Protocol
         Error that will affect the successful execution of
         subsequent commands and SQL statements: Reason Code
         "<reason-code(subcode)>".

Explanation:

A system error occurred that prevented successful execution of
the current environment command or SQL statement, as well as any
subsequent commands or SQL statements.

The subcode, when nonzero, consist of two bytes such that the
high-order byte indicates the site at which the error was
detected. This is X'01' if the error was detected by the local
DB2 server. It is X'02' if the error was detected by the remote
server. The low-order byte is an error code specific to the
reason code.

Reason code 124C indicates that the DRDA data stream for the
request contains a syntax error.

The command or statement cannot be processed.  The current
transaction is rolled back and the application is disconnected
from the remote database.

User Response:

Record the message number (SQLCODE) and the reason code.  Record
all error information from the SQLCA, if possible.  Attempt to
connect the remote database and rerun the application.

If sufficient memory resources exist and the problem continues,
invoke the Independent Trace Facility at the operating system
command prompt.

Required information:

o   Problem description

o   SQLCODE and reason code

o   SQLCA contents if possible

o   Trace file if possible.

Some possible reason codes include:

121C Indicates that the user is not authorized to perform the
requested command.

1232 The command could not be completed because of a permanent
error.  In most cases, the server will be in the process of an
abend.

1254 A command sent from the client has resulted in an
unarchitected and implementation specific condition on the remote
server for which there is no architected message to return to the
client.

If the remote server is DB2 UDB for OS/390,zOS then check the
console log for information about this error.

If the remote server is DB2 UDB for iSeries, the job log of the
server job, and/or a first failure data capture (FFDC) spooled
file is usually necessary to determine the cause of the error.

If the remote server is DB2 UDB for Unix/Windows then check the
remote database server's administration notification log for
information regarding this error.

220A The target server has received an invalid data description.
If a user SQLDA is specified, ensure that the fields are
initialized correctly.  Also, ensure that the length does not
exceed the maximum allowed length for the data type being used.

If you are using the DB2 Connect product in a gateway server
environment with downlevel clients, this error may occur if your
application's host variables and the queried table's column
descriptions do not match.

sqlcode :  -30020

sqlstate :  58009