error for cmod code - "Variables Contain Invalid Values"

hi all,

i am learning ABAP now.

trying to write code for a customer exit variable in tcode - CMOD.

PFA snapshots for the details.

"zfiscqtr.jpg" - this is the infoobject for which i have created a customer exit var and writing a code

"code.jpg" - this has the code that i have written

"msg-rsrt.jpg" - this has the error msg details , while trying to execute code in rsrt

logic needed:

current fiscal year qtr : say 20133 [means fiscal year is 2013 and fiscal qtr is 3]

i want to output , fiscal year qtr value that is 4quarters prior to currrent date.

so output to be 20123

pls suggest me on how to correct this error

regards,

swetha