Using SKILL to replace label text across multiple cells in a library using partial string match and replace

Hi all, I'm trying to replace label text in hundreds of cells in a library using partial string match. I found some old posts about similar activities and code it for this purpose, but it doesn't work. There are no error codes given, currently it just silently fails. I expect the error to be related to the rexMatchp, rexCompile, or rexReplace functions. If you spot where the error is, please comment!

For more context, the text labels I am trying to replace are of the format: "@AA.BB11C.DD0000EE.FF". They are there for the purpose of marking locations on the cells for software to understand the boundary of the cell and probe pad locations, and they are all slightly different, like a serial number. There are several hundred and are named incorrectly. I am trying to match the partial string "BB11" and change it to "BB12", so that the result would instead be named "@AA.BB12C.DD0000EE.FF"

Here's the code:

procedure( replaceLibLabels( libName findPattern replacePattern viewName "tt" )
let(
( libId cvId cellList labelList )



libId = ddGetObj( libName )
cellList = setof( cell libId~>cells member( viewName cell~>views~>name ))
foreach( cell cellList
cvId = dbOpenCellViewByType( libName cell~>name viewName nil "a" )
labelList = setof( shape cvId~>shapes shape~>objType == "label" && rexMatchp(findPattern shape~>theLabel) == t )
if(labelList
then
rexCompile(findPattern)
foreach( label labelList
rexReplace(label~>theLabel replacePattern 0)
)
dbSave( cvId )
)
dbClose( cvId )
)
))

Thank you!!