loading both RPostgreSQL and RSQLite leads to problems

hello,

if i load the RSQLite package in addition to the RPostgreSQL package,
i get various errors when trying to use RPostgreSQL functions. here is
an example transcript showing one such error:


==========================================================
R version 2.15.0 (2012-03-30)
[...]

packageVersion('RPostgreSQL')

[1]  0.3.2

packageVersion('RSQLite')

[1]  0.11.1

library(RPostgreSQL)

Loading required package: DBI

dbDriver('PostgreSQL')

<PostgreSQLDriver:(32540)>

library(RSQLite)
dbDriver('PostgreSQL')

Error in function (classes, fdef, mtable)  : 
 unable to find an inherited method for function "show", for signature "PostgreSQLDriver"
==========================================================


below is the output of showMethods('show') in two scenarios:
(1) RPostgreSQL loaded, RSQLite not loaded;
(2) RPostgreSQL loaded, RSQLite loaded (in that order).
i'd be grateful for any help resolving or working around this issue.
if possible, please include my email address in any reply.

best
jon mcauliffe
jon at mcauliffe.com



(1)

showMethods('show')

Function: show (package methods)
object="ANY"
object="classGeneratorFunction"
object="classRepresentation"
object="dbObjectId"
object="envRefClass"
object="function"
   (inherited from: object="ANY")
object="genericFunction"
object="genericFunctionWithTrace"
object="MethodDefinition"
object="MethodDefinitionWithTrace"
object="MethodSelectionReport"
object="MethodWithNext"
object="MethodWithNextWithTrace"
object="namedList"
object="ObjectsWithPackage"
object="oldClass"
object="PostgreSQLDriver"
   (inherited from: object="dbObjectId")
object="refClassRepresentation"
object="refMethodDef"
object="refObjectGenerator"
object="signature"
object="sourceEnvironment"
object="standardGeneric"
   (inherited from: object="genericFunction")
object="traceable"


(2)

showMethods('show')

Function: show (package methods)
object="ANY"
object="classGeneratorFunction"
object="classRepresentation"
 (2 methods defined for this signature, with different packages)
object="envRefClass"
object="genericFunction"
object="genericFunctionWithTrace"
object="MethodDefinition"
object="MethodDefinitionWithTrace"
object="MethodSelectionReport"
object="MethodWithNext"
object="MethodWithNextWithTrace"
object="namedList"
object="ObjectsWithPackage"
object="oldClass"
object="refClassRepresentation"
object="refMethodDef"
object="refObjectGenerator"
object="signature"
object="sourceEnvironment"
object="traceable"