Facing issue with illustrator automating svg creations

sure, Let me take the below use case,

I have an ai document where it contains about 400+ small symbols where each symbol is given a name & belongs to same layer in illustrator.

Use case:

step 1: Open this ai file & search through the name of the symbol & copy the symbol needed

step 2: Paste it in another document

step 3: above 1 & 2 will occur for all required symbols used (approx 10 times)

Code snippet:

For Each grp As Illustrator.GroupItem In SourceAIDocument.GroupItems
If Not grp Is Nothing Then
Try
If (grp.Name.ToString.Equals(uniqueSymbol.Key)) Then - The error occurs here
SourceAIDocument.Activate()-- document with symbols
Try
grp.Copy()

Catch ComEx As System.Runtime.InteropServices.COMException
Continue For

End If
Catch ex As Exception
Logger.WriteToLogError(Constants.ERRORS, ex.Message.ToString, "CopySymbolsInLocalAIFile")
End Try

TargetAIDocument.Activate()
Threading.Thread.Sleep(500)
Try

TargetAIDocument.Paste()
Threading.Thread.Sleep(500)
Exit For
Catch ComEx As System.Runtime.InteropServices.COMException
Continue For

Issue: While I search for the symbol by its name, I get this below error 

an Illustrator error occurred: 1346458189 ('PARM')

Please suggest some optimazition  that i can try for overcoming the above difficulty.

Note: I face similar issue while opening any document that contains few elements & try to copy & paste it.

Previously, with CS5 we didn't faced these issues , it was smooth.

Kindly advise if I can turnoff some features that will increase the performance of the illustrator as well.

Thanks,

Deepika