yep sure can, I don't need the new bells and whistles in R 3.0.0.

I'd still have a look at line 23 in AFNIio.R since it returns true regardless of whether the R_io.so loads successfully or not.

For example consider the following:
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> find.in.path <- function(file) { #Pretty much same as first.in.path
+ ff <- paste(strsplit(Sys.getenv('PATH'),':')[[1]],'/', file, sep='')
+ ff <- ff[lapply(ff,file.exists)==TRUE];
+ aa <- gsub('//','/',ff[1], fixed=TRUE)
+ if (is.na(aa)) aa <- NULL
+ return(aa)
+ }
> ll <- find.in.path('R_io.so')
> dd <- try(dyn.load(ll), silent=TRUE)
> dd
DLL name: R_io
Filename: /Volumes/opt/software/afni/R_io.so
Dynamic lookup: TRUE
> exists('dd')
[1] TRUE
#### Now try something I know doesn't exist and so will throw an error
> dd <- try(dyn.load(paste(ll, "1", sep="")), silent=TRUE)
> dd
[1] "Error in dyn.load(paste(ll, \"1\", sep = \"\")) : \n unable to load shared object '/Volumes/opt/software/afni/R_io.so1':\n dlopen(/Volumes/opt/software/afni/R_io.so1, 6): image not found\n"
attr(,"class")
[1] "try-error"
attr(,"condition")
<simpleError in dyn.load(paste(ll, "1", sep = "")): unable to load shared object '/Volumes/opt/software/afni/R_io.so1':
dlopen(/Volumes/opt/software/afni/R_io.so1, 6): image not found>
> exists('dd')
[1] TRUE