[Lazarus] TpOnGuard question

[Antônio]

Running StampExe.exe from IDE I get 201 RunTime error (Range Check
Error) on the first line of this IF statement (line 399):

if (PSignatureRec(@Memory[I]).Sig1 = $407E7E21) and
             (PSignatureRec(@Memory[I]).Sig2 = $33435243) and
             (PSignatureRec(@Memory[I]).Sig3 = $7E7E4032) and
             (PSignatureRec(@Memory[I]).Sig4 = $407E7E21) and
             (PSignatureRec(@Memory[I]).Sig5 = $33435243) and
             (PSignatureRec(@Memory[I]).Sig6 = $7E7E4032) then

How can I solve this?

Antônio