Although later I was successfully able to submit the solutions for TEST and PRIME1, PALIN is still experiencing the same fate. Another thing I noticed was that whenever SPOJ shows "Wrong Problem Code", ideone.com (which uses SPOJ engine) also shows "not running" (not runtime error or compilation error). It seems, in general, that sometimes due to some server error, there is some problem in solution submission while rest of the time it works fine. Kindly look into the matter.