Error "CALL_FUNTION_NOT_FOUND" in CRM2007

Question

Hi All,
     Customer is using crm2007 system. When he try to execute a prog "ztest" he is getting dump with CALL_FUNTION_NOT_FOUN & Exception is CX_SY_CALL_ILLEGAL_FUNC.
    1. FM: POPUP_TO_DISPLAY_TEXT is existing in crm2007 system or not?
    2. If yes, what might be other resons for this dump.
I searched for sap notes, still need more clarification.
Runtime Errors CALL_FUNCTION_NOT_FOUND
Except. CX_SY_DYN_CALL_ILLEGAL_FUNC
ShortText
Function module "POPUP_TO_DISPLAY_TEXT " not found.
What happened?
The function module "POPUP_TO_DISPLAY_TEXT " was called, but cannot be
found in the Function Library.
Error in ABAP application program.
The current ABAP program "ztest" had to be terminated because it has
come across a statement that unfortunately cannot be executed.
Error analysis
  An exception occurred. This exception is dealt with in more detail below. The exception, which is assigned to the class 'CX_SY_DYN_CALL_ILLEGAL_FUNC', was neither
caught nor passed along using a RAISING clause, in the procedure
"FORM name" "(FORM)"
Since the caller of the procedure could not have expected this exception
to occur, the running program was terminated.
The reason for the exception is:
The program "ztest" contains a CALL FUNCTION statement. The name
of the function module to be called is "POPUP_TO_DISPLAY_TEXT ".
No function module exists with the name "POPUP_TO_DISPLAY_TEXT ".
All function modules are stored in the Function Library (SE37).
Possible reasons:
a) Wrong name specified. Particular attention should be paid
to upper/lower case and underscores ("_")
b) Transport error
c) If an enqueue/dequeue module has been used, the lock object
may not have been activated (ABAP Dictionary)
Please suggest me how to rectify this...
Regards,

Answer 1

It is not necessary for an ECC function module to be found in CRM2007. Moreover, CRM2007 has WebGUI so there is no need for calling this function module.