Avoid double posting within 6 hours. Use the edit button instead.
What exactly do you have in Str4 ? Dou you have just "PROGNAME" in it or do you have "prgmPROGNAME" (where PROGNAME is the name of your program) ?

Just did a little test program.

.TEST

"BLARG"→Str1
.Str1 is data to be copied

"prgmSTORE"→Str2
.Str2 is program to be searched for

GetCalc(Str2)→P
.P is pointer

!If P
Disp "Error"
Return
.handle error etc
End

Length(Str1)→A
Copy(Str1,P,A)

If the program is 10 bytes when you first made it, it should look something like this when viewed in the editor:

Oh then just replace "StrX" with "prgmWHATEVER".

As far as I can understand, you want to create a program with the name stored in the OS variable Str4 and the contents stored in the OS variable Str1? If so, here's what I've come up with. I made two different versions: one is larger and allows you to handle each error that could occur individually, while the other is smaller and doesn't support error handling (errors are still caught and avoided, they just cannot be acted upon). The source for both versions is included as text below and as programs attached at the bottom of this post.


With error handling:
!If GetCalc("Str1")→S
 .Str1 not found
Else
 !If GetCalc("Str4")→N
  .Str4 not found
 Else
  .L₁ can be replaced with any section of safe RAM at least 9 bytes large
  'prgm'→{L₁}ʳ
  Fill(L₁+1,8)
  Copy(N,L₁+1,{N-2}ʳ)
  !If GetCalc(L₁,{S-2}ʳ→L)→P
   .Creation error
  Else
   Copy(S,P,L)
  End
 End
End

Without error handling:
If GetCalc("Str4")→N
 .L₁ can be replaced with any section of safe RAM at least 9 bytes large
 'prgm'→{L₁}ʳ
 Fill(L₁+1,8)
 Copy(N,L₁+1,{N-2}ʳ)
 If GetCalc("Str1")→S
  Copy(S,GetCalc(L₁,{S-2}ʳ→L),L)
 End
End