How to trigger a proxy in SAP PI 7.1

Question

Dear friends
  How are you? I am not able to calla proxy in my system,  it throws the dump error like
The reason for the exception is:
You attempted to use a 'NULL' object reference (points to 'nothing')
access a component.
An object reference must point to an object (an instance of a class)
before it can be used to access components.
Either the reference was never set or it was set to 'NULL' using the
CLEAR statement.
I have one function module in that I am calling method to execute proxy.
this is the way.
data: proxy_create_acc type ref to ZCL_SI_ACCOUNT_CRT,
      lv_param_t type standard table of ZMT_ACCOUNT_CR_T,
      lv_param_l type ZMT_ACCOUNT_CR_T,
      im_account type ZDT_ACCOUNT_CRT.
      im_account-account_name = 'BABINS'.
      im_account-value = im_param.
      lv_param_l-MT_ACCOUNT_CR_T = im_account. ,
      APPEND lv_param_l to lv_param_t . <- this has the data
TRY.
CALL METHOD proxy_create_acc->ZII_SI_ACCOUNT_CRT~si_account_crt  <-- error is here
  EXPORTING
    input  = lv_param_l. <-this has the data
commit work.
CATCH zcx_ft_fault_acr .
    DATA fault TYPE REF TO ZCX_FT_FAULT_ACR .
    data textid type SOTR_CONC.
    data message type STRING.
    CREATE OBJECT fault.
    return-id  = '001'.
    textid = fault->TEXTID.
ENDTRY.
Am I writing wrong. please  help me to currect this error, your any help will be appreciated. thank you so much.

Answer 1

Seems you have not created object of the class before using its method.
Use CREATE OBJECT proxy_create_acc before calling method of the class.